1
00:00:11,110 --> 00:00:13,680
see this has like seven carbon wonder

2
00:00:13,680 --> 00:00:13,690
see this has like seven carbon wonder

3
00:00:13,690 --> 00:00:15,930
see this has like seven carbon wonder
eight carbon here a long chain like this

4
00:00:15,930 --> 00:00:15,940
eight carbon here a long chain like this

5
00:00:15,940 --> 00:00:21,269
eight carbon here a long chain like this
and the liquid crystal properties

6
00:00:21,269 --> 00:00:21,279
and the liquid crystal properties

7
00:00:21,279 --> 00:00:24,510
and the liquid crystal properties
observed between 108 and hundred 47

8
00:00:24,510 --> 00:00:24,520
observed between 108 and hundred 47

9
00:00:24,520 --> 00:00:27,179
observed between 108 and hundred 47
degrees centigrade in this case 21 and

10
00:00:27,179 --> 00:00:27,189
degrees centigrade in this case 21 and

11
00:00:27,189 --> 00:00:33,240
degrees centigrade in this case 21 and
47 degrees centigrade okay chapter 12 is

12
00:00:33,240 --> 00:00:33,250
47 degrees centigrade okay chapter 12 is

13
00:00:33,250 --> 00:00:38,430
47 degrees centigrade okay chapter 12 is
about solids and modern materials now we

14
00:00:38,430 --> 00:00:38,440
about solids and modern materials now we

15
00:00:38,440 --> 00:00:40,710
about solids and modern materials now we
talked about the properties of solids in

16
00:00:40,710 --> 00:00:40,720
talked about the properties of solids in

17
00:00:40,720 --> 00:00:44,279
talked about the properties of solids in
general actually we said that the solids

18
00:00:44,279 --> 00:00:44,289
general actually we said that the solids

19
00:00:44,289 --> 00:00:49,110
general actually we said that the solids
are made of molecules may be made of

20
00:00:49,110 --> 00:00:49,120
are made of molecules may be made of

21
00:00:49,120 --> 00:00:52,349
are made of molecules may be made of
molecules ions or atoms and the solid

22
00:00:52,349 --> 00:00:52,359
molecules ions or atoms and the solid

23
00:00:52,359 --> 00:00:54,930
molecules ions or atoms and the solid
state the atoms molecules or the ions

24
00:00:54,930 --> 00:00:54,940
state the atoms molecules or the ions

25
00:00:54,940 --> 00:00:59,310
state the atoms molecules or the ions
whatever makes the solid only vibrate

26
00:00:59,310 --> 00:00:59,320
whatever makes the solid only vibrate

27
00:00:59,320 --> 00:01:01,529
whatever makes the solid only vibrate
make vibration motions but they are not

28
00:01:01,529 --> 00:01:01,539
make vibration motions but they are not

29
00:01:01,539 --> 00:01:04,979
make vibration motions but they are not
free to move in the solid and that's why

30
00:01:04,979 --> 00:01:04,989
free to move in the solid and that's why

31
00:01:04,989 --> 00:01:09,210
free to move in the solid and that's why
the solid stays same shape and so on and

32
00:01:09,210 --> 00:01:09,220
the solid stays same shape and so on and

33
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the solid stays same shape and so on and
we also talked about the Dalton points

34
00:01:14,310 --> 00:01:14,320
we also talked about the Dalton points

35
00:01:14,320 --> 00:01:16,650
we also talked about the Dalton points
of service and so on compared the

36
00:01:16,650 --> 00:01:16,660
of service and so on compared the

37
00:01:16,660 --> 00:01:20,010
of service and so on compared the
physical properties of solid liquid and

38
00:01:20,010 --> 00:01:20,020
physical properties of solid liquid and

39
00:01:20,020 --> 00:01:22,530
physical properties of solid liquid and
gases actually and try to explain them

40
00:01:22,530 --> 00:01:22,540
gases actually and try to explain them

41
00:01:22,540 --> 00:01:25,590
gases actually and try to explain them
with the molecular level properties of

42
00:01:25,590 --> 00:01:25,600
with the molecular level properties of

43
00:01:25,600 --> 00:01:30,330
with the molecular level properties of
the substances made of it now here now

44
00:01:30,330 --> 00:01:30,340
the substances made of it now here now

45
00:01:30,340 --> 00:01:33,660
the substances made of it now here now
chapter 10 which we have skipped

46
00:01:33,660 --> 00:01:33,670
chapter 10 which we have skipped

47
00:01:33,670 --> 00:01:35,580
chapter 10 which we have skipped
actually and we left it to you you're

48
00:01:35,580 --> 00:01:35,590
actually and we left it to you you're

49
00:01:35,590 --> 00:01:37,410
actually and we left it to you you're
supposed to read it it's about the

50
00:01:37,410 --> 00:01:37,420
supposed to read it it's about the

51
00:01:37,420 --> 00:01:41,340
supposed to read it it's about the
gaseous state now chapter 11 we just

52
00:01:41,340 --> 00:01:41,350
gaseous state now chapter 11 we just

53
00:01:41,350 --> 00:01:43,830
gaseous state now chapter 11 we just
finished that's about the more liquid

54
00:01:43,830 --> 00:01:43,840
finished that's about the more liquid

55
00:01:43,840 --> 00:01:47,670
finished that's about the more liquid
state right describes the liquid state

56
00:01:47,670 --> 00:01:47,680
state right describes the liquid state

57
00:01:47,680 --> 00:01:49,710
state right describes the liquid state
properties properties of the liquid now

58
00:01:49,710 --> 00:01:49,720
properties properties of the liquid now

59
00:01:49,720 --> 00:01:51,660
properties properties of the liquid now
this chapter 12 is about the solid you

60
00:01:51,660 --> 00:01:51,670
this chapter 12 is about the solid you

61
00:01:51,670 --> 00:01:54,950
this chapter 12 is about the solid you
see again these three chapters 10 11 12

62
00:01:54,950 --> 00:01:54,960
see again these three chapters 10 11 12

63
00:01:54,960 --> 00:01:59,130
see again these three chapters 10 11 12
simply about the states of matter gas

64
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simply about the states of matter gas

65
00:01:59,140 --> 00:02:03,210
simply about the states of matter gas
liquids and solids now let's look at the

66
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liquids and solids now let's look at the

67
00:02:03,220 --> 00:02:06,480
liquids and solids now let's look at the
solids stage again now there are certain

68
00:02:06,480 --> 00:02:06,490
solids stage again now there are certain

69
00:02:06,490 --> 00:02:09,660
solids stage again now there are certain
ways of classifying solids one way

70
00:02:09,660 --> 00:02:09,670
ways of classifying solids one way

71
00:02:09,670 --> 00:02:12,059
ways of classifying solids one way
classifying the solids is according to

72
00:02:12,059 --> 00:02:12,069
classifying the solids is according to

73
00:02:12,069 --> 00:02:15,330
classifying the solids is according to
the bunks that keeps these solid

74
00:02:15,330 --> 00:02:15,340
the bunks that keeps these solid

75
00:02:15,340 --> 00:02:18,150
the bunks that keeps these solid
molecules or whatever solid is made off

76
00:02:18,150 --> 00:02:18,160
molecules or whatever solid is made off

77
00:02:18,160 --> 00:02:21,570
molecules or whatever solid is made off
the unit's together and according to

78
00:02:21,570 --> 00:02:21,580
the unit's together and according to

79
00:02:21,580 --> 00:02:24,840
the unit's together and according to
this classification based on the bond

80
00:02:24,840 --> 00:02:24,850
this classification based on the bond

81
00:02:24,850 --> 00:02:29,370
this classification based on the bond
actually that means forces that holds up

82
00:02:29,370 --> 00:02:29,380
actually that means forces that holds up

83
00:02:29,380 --> 00:02:32,250
actually that means forces that holds up
the molecules or in the solid states are

84
00:02:32,250 --> 00:02:32,260
the molecules or in the solid states are

85
00:02:32,260 --> 00:02:37,410
the molecules or in the solid states are
metallic solids ionic solids covalent

86
00:02:37,410 --> 00:02:37,420
metallic solids ionic solids covalent

87
00:02:37,420 --> 00:02:40,970
metallic solids ionic solids covalent
Network solids molecular solids and

88
00:02:40,970 --> 00:02:40,980
Network solids molecular solids and

89
00:02:40,980 --> 00:02:44,520
Network solids molecular solids and
polymer polymers these are again solids

90
00:02:44,520 --> 00:02:44,530
polymer polymers these are again solids

91
00:02:44,530 --> 00:02:48,210
polymer polymers these are again solids
and nano materials now let's look at

92
00:02:48,210 --> 00:02:48,220
and nano materials now let's look at

93
00:02:48,220 --> 00:02:52,950
and nano materials now let's look at
what are the forces that held the solid

94
00:02:52,950 --> 00:02:52,960
what are the forces that held the solid

95
00:02:52,960 --> 00:02:55,620
what are the forces that held the solid
molecules or atoms together in the

96
00:02:55,620 --> 00:02:55,630
molecules or atoms together in the

97
00:02:55,630 --> 00:02:58,500
molecules or atoms together in the
metallic solids again as we see here are

98
00:02:58,500 --> 00:02:58,510
metallic solids again as we see here are

99
00:02:58,510 --> 00:03:02,580
metallic solids again as we see here are
held together by sea of collectively

100
00:03:02,580 --> 00:03:02,590
held together by sea of collectively

101
00:03:02,590 --> 00:03:07,250
held together by sea of collectively
shared electrons what does this means

102
00:03:07,250 --> 00:03:07,260
shared electrons what does this means

103
00:03:07,260 --> 00:03:14,790
shared electrons what does this means
what is this what are the forces that

104
00:03:14,790 --> 00:03:14,800
what is this what are the forces that

105
00:03:14,800 --> 00:03:19,350
what is this what are the forces that
keep the solid metals together in a

106
00:03:19,350 --> 00:03:19,360
keep the solid metals together in a

107
00:03:19,360 --> 00:03:23,430
keep the solid metals together in a
solid form it's actually might alec bond

108
00:03:23,430 --> 00:03:23,440
solid form it's actually might alec bond

109
00:03:23,440 --> 00:03:25,290
solid form it's actually might alec bond
remember it's a metallic bond what we

110
00:03:25,290 --> 00:03:25,300
remember it's a metallic bond what we

111
00:03:25,300 --> 00:03:28,530
remember it's a metallic bond what we
said metallic bond is the attraction

112
00:03:28,530 --> 00:03:28,540
said metallic bond is the attraction

113
00:03:28,540 --> 00:03:32,250
said metallic bond is the attraction
between the electron cloud that moves

114
00:03:32,250 --> 00:03:32,260
between the electron cloud that moves

115
00:03:32,260 --> 00:03:36,240
between the electron cloud that moves
freely in the metal and the positively

116
00:03:36,240 --> 00:03:36,250
freely in the metal and the positively

117
00:03:36,250 --> 00:03:39,210
freely in the metal and the positively
charged metal ions right this is a

118
00:03:39,210 --> 00:03:39,220
charged metal ions right this is a

119
00:03:39,220 --> 00:03:41,040
charged metal ions right this is a
chemical bond actually one type of

120
00:03:41,040 --> 00:03:41,050
chemical bond actually one type of

121
00:03:41,050 --> 00:03:42,780
chemical bond actually one type of
chemical bond and it's a very very

122
00:03:42,780 --> 00:03:42,790
chemical bond and it's a very very

123
00:03:42,790 --> 00:03:45,780
chemical bond and it's a very very
strong and in metals actually the force

124
00:03:45,780 --> 00:03:45,790
strong and in metals actually the force

125
00:03:45,790 --> 00:03:48,900
strong and in metals actually the force
that keeps the battle together actually

126
00:03:48,900 --> 00:03:48,910
that keeps the battle together actually

127
00:03:48,910 --> 00:03:52,500
that keeps the battle together actually
is the metallic bond now ionic solids as

128
00:03:52,500 --> 00:03:52,510
is the metallic bond now ionic solids as

129
00:03:52,510 --> 00:03:55,140
is the metallic bond now ionic solids as
we talked about this also ionic solids

130
00:03:55,140 --> 00:03:55,150
we talked about this also ionic solids

131
00:03:55,150 --> 00:03:58,250
we talked about this also ionic solids
are also held together by the

132
00:03:58,250 --> 00:03:58,260
are also held together by the

133
00:03:58,260 --> 00:04:00,320
are also held together by the
electrostatic attraction between

134
00:04:00,320 --> 00:04:00,330
electrostatic attraction between

135
00:04:00,330 --> 00:04:03,060
electrostatic attraction between
positive and negatively charged ions and

136
00:04:03,060 --> 00:04:03,070
positive and negatively charged ions and

137
00:04:03,070 --> 00:04:08,880
positive and negatively charged ions and
what is this ionic bond right actually

138
00:04:08,880 --> 00:04:08,890
what is this ionic bond right actually

139
00:04:08,890 --> 00:04:12,480
what is this ionic bond right actually
it is ionic bonds so in ionic solids

140
00:04:12,480 --> 00:04:12,490
it is ionic bonds so in ionic solids

141
00:04:12,490 --> 00:04:15,540
it is ionic bonds so in ionic solids
actually we have the ionic bonds and

142
00:04:15,540 --> 00:04:15,550
actually we have the ionic bonds and

143
00:04:15,550 --> 00:04:18,270
actually we have the ionic bonds and
that ionic bonds keep the ionic solid

144
00:04:18,270 --> 00:04:18,280
that ionic bonds keep the ionic solid

145
00:04:18,280 --> 00:04:21,450
that ionic bonds keep the ionic solid
together now covalent Network solids

146
00:04:21,450 --> 00:04:21,460
together now covalent Network solids

147
00:04:21,460 --> 00:04:23,490
together now covalent Network solids
what is it for example example the metal

148
00:04:23,490 --> 00:04:23,500
what is it for example example the metal

149
00:04:23,500 --> 00:04:26,700
what is it for example example the metal
solids examples are any metals ayran

150
00:04:26,700 --> 00:04:26,710
solids examples are any metals ayran

151
00:04:26,710 --> 00:04:30,120
solids examples are any metals ayran
gold copper whatever nickel and so on

152
00:04:30,120 --> 00:04:30,130
gold copper whatever nickel and so on

153
00:04:30,130 --> 00:04:32,760
gold copper whatever nickel and so on
now ionic solids are ionic compounds

154
00:04:32,760 --> 00:04:32,770
now ionic solids are ionic compounds

155
00:04:32,770 --> 00:04:34,830
now ionic solids are ionic compounds
such as the sodium chloride cesium

156
00:04:34,830 --> 00:04:34,840
such as the sodium chloride cesium

157
00:04:34,840 --> 00:04:37,350
such as the sodium chloride cesium
chloride or sodium fluoride and so on

158
00:04:37,350 --> 00:04:37,360
chloride or sodium fluoride and so on

159
00:04:37,360 --> 00:04:38,640
chloride or sodium fluoride and so on
that means in this

160
00:04:38,640 --> 00:04:38,650
that means in this

161
00:04:38,650 --> 00:04:41,820
that means in this
our state exists in form of ions

162
00:04:41,820 --> 00:04:41,830
our state exists in form of ions

163
00:04:41,830 --> 00:04:44,040
our state exists in form of ions
positive and negatively charged ions now

164
00:04:44,040 --> 00:04:44,050
positive and negatively charged ions now

165
00:04:44,050 --> 00:04:46,830
positive and negatively charged ions now
covalent Network solids are joined by an

166
00:04:46,830 --> 00:04:46,840
covalent Network solids are joined by an

167
00:04:46,840 --> 00:04:51,719
covalent Network solids are joined by an
extensive network of covalent bonds now

168
00:04:51,719 --> 00:04:51,729
extensive network of covalent bonds now

169
00:04:51,729 --> 00:04:55,920
extensive network of covalent bonds now
one example is diamond now in diamond

170
00:04:55,920 --> 00:04:55,930
one example is diamond now in diamond

171
00:04:55,930 --> 00:04:59,400
one example is diamond now in diamond
actually every carbon atom is bonded to

172
00:04:59,400 --> 00:04:59,410
actually every carbon atom is bonded to

173
00:04:59,410 --> 00:05:01,469
actually every carbon atom is bonded to
the other carbon atom by covalent bond

174
00:05:01,469 --> 00:05:01,479
the other carbon atom by covalent bond

175
00:05:01,479 --> 00:05:05,580
the other carbon atom by covalent bond
and it expands over all solid diamond

176
00:05:05,580 --> 00:05:05,590
and it expands over all solid diamond

177
00:05:05,590 --> 00:05:08,580
and it expands over all solid diamond
it's a very very strong covalent bonds

178
00:05:08,580 --> 00:05:08,590
it's a very very strong covalent bonds

179
00:05:08,590 --> 00:05:12,689
it's a very very strong covalent bonds
and that makes the diamond actually very

180
00:05:12,689 --> 00:05:12,699
and that makes the diamond actually very

181
00:05:12,699 --> 00:05:16,320
and that makes the diamond actually very
very stable very hard so on right so

182
00:05:16,320 --> 00:05:16,330
very stable very hard so on right so

183
00:05:16,330 --> 00:05:18,840
very stable very hard so on right so
those are the covalent Network solids

184
00:05:18,840 --> 00:05:18,850
those are the covalent Network solids

185
00:05:18,850 --> 00:05:20,879
those are the covalent Network solids
our exam one example is diamond or

186
00:05:20,879 --> 00:05:20,889
our exam one example is diamond or

187
00:05:20,889 --> 00:05:24,510
our exam one example is diamond or
graphite or all carbon actually that's

188
00:05:24,510 --> 00:05:24,520
graphite or all carbon actually that's

189
00:05:24,520 --> 00:05:27,529
graphite or all carbon actually that's
also diamond remember it's also carbon

190
00:05:27,529 --> 00:05:27,539
also diamond remember it's also carbon

191
00:05:27,539 --> 00:05:30,589
also diamond remember it's also carbon
but graphite is a different form of

192
00:05:30,589 --> 00:05:30,599
but graphite is a different form of

193
00:05:30,599 --> 00:05:36,749
but graphite is a different form of
carbon again and silicon and silicon

194
00:05:36,749 --> 00:05:36,759
carbon again and silicon and silicon

195
00:05:36,759 --> 00:05:37,379
carbon again and silicon and silicon
dioxide

196
00:05:37,379 --> 00:05:37,389
dioxide

197
00:05:37,389 --> 00:05:40,650
dioxide
all of these are covalent Network solids

198
00:05:40,650 --> 00:05:40,660
all of these are covalent Network solids

199
00:05:40,660 --> 00:05:42,659
all of these are covalent Network solids
that means that the atoms are bonded

200
00:05:42,659 --> 00:05:42,669
that means that the atoms are bonded

201
00:05:42,669 --> 00:05:46,980
that means that the atoms are bonded
together by covalent bonds and this

202
00:05:46,980 --> 00:05:46,990
together by covalent bonds and this

203
00:05:46,990 --> 00:05:48,900
together by covalent bonds and this
covalent bonds is the network type that

204
00:05:48,900 --> 00:05:48,910
covalent bonds is the network type that

205
00:05:48,910 --> 00:05:52,110
covalent bonds is the network type that
means it's over all the covers the whole

206
00:05:52,110 --> 00:05:52,120
means it's over all the covers the whole

207
00:05:52,120 --> 00:05:54,839
means it's over all the covers the whole
solid covers the whole solid and they're

208
00:05:54,839 --> 00:05:54,849
solid covers the whole solid and they're

209
00:05:54,849 --> 00:05:58,140
solid covers the whole solid and they're
very very strong again molecular solids

210
00:05:58,140 --> 00:05:58,150
very very strong again molecular solids

211
00:05:58,150 --> 00:06:01,020
very very strong again molecular solids
are discrete molecules has together by

212
00:06:01,020 --> 00:06:01,030
are discrete molecules has together by

213
00:06:01,030 --> 00:06:04,560
are discrete molecules has together by
weak forces what are these forces these

214
00:06:04,560 --> 00:06:04,570
weak forces what are these forces these

215
00:06:04,570 --> 00:06:09,529
weak forces what are these forces these
are intermolecular forces London forces

216
00:06:09,529 --> 00:06:09,539
are intermolecular forces London forces

217
00:06:09,539 --> 00:06:12,589
are intermolecular forces London forces
right London dispersion forces or

218
00:06:12,589 --> 00:06:12,599
right London dispersion forces or

219
00:06:12,599 --> 00:06:17,250
right London dispersion forces or
dipole-dipole forces or hydrogen bonding

220
00:06:17,250 --> 00:06:17,260
dipole-dipole forces or hydrogen bonding

221
00:06:17,260 --> 00:06:20,070
dipole-dipole forces or hydrogen bonding
these are the forces that keep the

222
00:06:20,070 --> 00:06:20,080
these are the forces that keep the

223
00:06:20,080 --> 00:06:21,689
these are the forces that keep the
molecular solids together as a matter of

224
00:06:21,689 --> 00:06:21,699
molecular solids together as a matter of

225
00:06:21,699 --> 00:06:25,700
molecular solids together as a matter of
fact now if you simply if I ask you

226
00:06:25,700 --> 00:06:25,710
fact now if you simply if I ask you

227
00:06:25,710 --> 00:06:29,600
fact now if you simply if I ask you
which of these solids will have the

228
00:06:29,600 --> 00:06:29,610
which of these solids will have the

229
00:06:29,610 --> 00:06:33,930
which of these solids will have the
highest mountain point remember again

230
00:06:33,930 --> 00:06:33,940
highest mountain point remember again

231
00:06:33,940 --> 00:06:36,570
highest mountain point remember again
the mountain point is also determined by

232
00:06:36,570 --> 00:06:36,580
the mountain point is also determined by

233
00:06:36,580 --> 00:06:41,310
the mountain point is also determined by
the degree of attractions of the solid

234
00:06:41,310 --> 00:06:41,320
the degree of attractions of the solid

235
00:06:41,320 --> 00:06:43,740
the degree of attractions of the solid
particles or molecules together and in

236
00:06:43,740 --> 00:06:43,750
particles or molecules together and in

237
00:06:43,750 --> 00:06:46,170
particles or molecules together and in
terms of that highest will be actually

238
00:06:46,170 --> 00:06:46,180
terms of that highest will be actually

239
00:06:46,180 --> 00:06:48,420
terms of that highest will be actually
this covalent solids has very very

240
00:06:48,420 --> 00:06:48,430
this covalent solids has very very

241
00:06:48,430 --> 00:06:50,070
this covalent solids has very very
strong and they are very very high

242
00:06:50,070 --> 00:06:50,080
strong and they are very very high

243
00:06:50,080 --> 00:06:52,140
strong and they are very very high
melting points as a matter of fact next

244
00:06:52,140 --> 00:06:52,150
melting points as a matter of fact next

245
00:06:52,150 --> 00:06:52,860
melting points as a matter of fact next
will be

246
00:06:52,860 --> 00:06:52,870
will be

247
00:06:52,870 --> 00:06:55,860
will be
we ionic solids ionic solids and the

248
00:06:55,860 --> 00:06:55,870
we ionic solids ionic solids and the

249
00:06:55,870 --> 00:06:57,810
we ionic solids ionic solids and the
metallic solids remember there are

250
00:06:57,810 --> 00:06:57,820
metallic solids remember there are

251
00:06:57,820 --> 00:07:01,920
metallic solids remember there are
metals that melts at room temperature 28

252
00:07:01,920 --> 00:07:01,930
metals that melts at room temperature 28

253
00:07:01,930 --> 00:07:04,080
metals that melts at room temperature 28
degrees 30 degrees actually room

254
00:07:04,080 --> 00:07:04,090
degrees 30 degrees actually room

255
00:07:04,090 --> 00:07:06,330
degrees 30 degrees actually room
temperature 25 but little about that but

256
00:07:06,330 --> 00:07:06,340
temperature 25 but little about that but

257
00:07:06,340 --> 00:07:10,410
temperature 25 but little about that but
there are metals that melts at 3000

258
00:07:10,410 --> 00:07:10,420
there are metals that melts at 3000

259
00:07:10,420 --> 00:07:12,660
there are metals that melts at 3000
degrees centigrade what is that the

260
00:07:12,660 --> 00:07:12,670
degrees centigrade what is that the

261
00:07:12,670 --> 00:07:18,860
degrees centigrade what is that the
highest melting point for the metals yes

262
00:07:18,860 --> 00:07:18,870
highest melting point for the metals yes

263
00:07:18,870 --> 00:07:25,190
highest melting point for the metals yes
which metal tungsten right remember the

264
00:07:25,190 --> 00:07:25,200
which metal tungsten right remember the

265
00:07:25,200 --> 00:07:29,070
which metal tungsten right remember the
light bulbs inside the light bulb we

266
00:07:29,070 --> 00:07:29,080
light bulbs inside the light bulb we

267
00:07:29,080 --> 00:07:31,380
light bulbs inside the light bulb we
have the resistance wire that resistance

268
00:07:31,380 --> 00:07:31,390
have the resistance wire that resistance

269
00:07:31,390 --> 00:07:33,480
have the resistance wire that resistance
wire actually is tungsten and that

270
00:07:33,480 --> 00:07:33,490
wire actually is tungsten and that

271
00:07:33,490 --> 00:07:36,030
wire actually is tungsten and that
tungsten melts over 3000 degrees

272
00:07:36,030 --> 00:07:36,040
tungsten melts over 3000 degrees

273
00:07:36,040 --> 00:07:39,630
tungsten melts over 3000 degrees
centigrade that resistant gets so hot

274
00:07:39,630 --> 00:07:39,640
centigrade that resistant gets so hot

275
00:07:39,640 --> 00:07:41,880
centigrade that resistant gets so hot
but still stays together as solid and

276
00:07:41,880 --> 00:07:41,890
but still stays together as solid and

277
00:07:41,890 --> 00:07:45,360
but still stays together as solid and
you see again in the saw metal cases

278
00:07:45,360 --> 00:07:45,370
you see again in the saw metal cases

279
00:07:45,370 --> 00:07:47,580
you see again in the saw metal cases
depending on the metal the melting

280
00:07:47,580 --> 00:07:47,590
depending on the metal the melting

281
00:07:47,590 --> 00:07:49,440
depending on the metal the melting
points are variable but the molecular

282
00:07:49,440 --> 00:07:49,450
points are variable but the molecular

283
00:07:49,450 --> 00:07:53,790
points are variable but the molecular
solids usually have low melting points

284
00:07:53,790 --> 00:07:53,800
solids usually have low melting points

285
00:07:53,800 --> 00:07:57,420
solids usually have low melting points
because the forces that keeps that

286
00:07:57,420 --> 00:07:57,430
because the forces that keeps that

287
00:07:57,430 --> 00:07:59,730
because the forces that keeps that
together solid in fact particles

288
00:07:59,730 --> 00:07:59,740
together solid in fact particles

289
00:07:59,740 --> 00:08:01,520
together solid in fact particles
together in the molecular solids are

290
00:08:01,520 --> 00:08:01,530
together in the molecular solids are

291
00:08:01,530 --> 00:08:03,780
together in the molecular solids are
intermolecular forces intermolecular

292
00:08:03,780 --> 00:08:03,790
intermolecular forces intermolecular

293
00:08:03,790 --> 00:08:09,320
intermolecular forces intermolecular
forces now polymers again here these are

294
00:08:09,320 --> 00:08:09,330
forces now polymers again here these are

295
00:08:09,330 --> 00:08:14,040
forces now polymers again here these are
chains of the atoms long big molecules

296
00:08:14,040 --> 00:08:14,050
chains of the atoms long big molecules

297
00:08:14,050 --> 00:08:17,390
chains of the atoms long big molecules
and they usually have a unit and

298
00:08:17,390 --> 00:08:17,400
and they usually have a unit and

299
00:08:17,400 --> 00:08:19,710
and they usually have a unit and
polymerizations of that human unit gives

300
00:08:19,710 --> 00:08:19,720
polymerizations of that human unit gives

301
00:08:19,720 --> 00:08:23,010
polymerizations of that human unit gives
you polymers and it gives again long

302
00:08:23,010 --> 00:08:23,020
you polymers and it gives again long

303
00:08:23,020 --> 00:08:25,290
you polymers and it gives again long
chain of atoms connected by covalent

304
00:08:25,290 --> 00:08:25,300
chain of atoms connected by covalent

305
00:08:25,300 --> 00:08:28,190
chain of atoms connected by covalent
bonds and the chains can be connected to

306
00:08:28,190 --> 00:08:28,200
bonds and the chains can be connected to

307
00:08:28,200 --> 00:08:31,200
bonds and the chains can be connected to
other chain by weak forces now weak

308
00:08:31,200 --> 00:08:31,210
other chain by weak forces now weak

309
00:08:31,210 --> 00:08:33,810
other chain by weak forces now weak
forces when we say that's intermolecular

310
00:08:33,810 --> 00:08:33,820
forces when we say that's intermolecular

311
00:08:33,820 --> 00:08:45,520
forces when we say that's intermolecular
forces again

312
00:08:45,520 --> 00:08:45,530

313
00:08:45,530 --> 00:08:47,630
these molecules have different

314
00:08:47,630 --> 00:08:47,640
these molecules have different

315
00:08:47,640 --> 00:08:49,940
these molecules have different
properties than small molecules or

316
00:08:49,940 --> 00:08:49,950
properties than small molecules or

317
00:08:49,950 --> 00:08:53,180
properties than small molecules or
metallic or ionic compounds again we

318
00:08:53,180 --> 00:08:53,190
metallic or ionic compounds again we

319
00:08:53,190 --> 00:08:56,060
metallic or ionic compounds again we
know in polymers you know all over and

320
00:08:56,060 --> 00:08:56,070
know in polymers you know all over and

321
00:08:56,070 --> 00:08:58,190
know in polymers you know all over and
we use them every day they're actually

322
00:08:58,190 --> 00:08:58,200
we use them every day they're actually

323
00:08:58,200 --> 00:09:01,600
we use them every day they're actually
made of long molecules bonded together

324
00:09:01,600 --> 00:09:01,610
made of long molecules bonded together

325
00:09:01,610 --> 00:09:03,950
made of long molecules bonded together
chains of atoms bonded together by

326
00:09:03,950 --> 00:09:03,960
chains of atoms bonded together by

327
00:09:03,960 --> 00:09:07,160
chains of atoms bonded together by
covalent bond now none of materials

328
00:09:07,160 --> 00:09:07,170
covalent bond now none of materials

329
00:09:07,170 --> 00:09:11,900
covalent bond now none of materials
these are again new type of solids like

330
00:09:11,900 --> 00:09:11,910
these are again new type of solids like

331
00:09:11,910 --> 00:09:14,390
these are again new type of solids like
10 or 20 years ago in general chemistry

332
00:09:14,390 --> 00:09:14,400
10 or 20 years ago in general chemistry

333
00:09:14,400 --> 00:09:18,470
10 or 20 years ago in general chemistry
book you will never find mentioning

334
00:09:18,470 --> 00:09:18,480
book you will never find mentioning

335
00:09:18,480 --> 00:09:21,710
book you will never find mentioning
about this nano materials nano materials

336
00:09:21,710 --> 00:09:21,720
about this nano materials nano materials

337
00:09:21,720 --> 00:09:24,890
about this nano materials nano materials
but they are very important now and very

338
00:09:24,890 --> 00:09:24,900
but they are very important now and very

339
00:09:24,900 --> 00:09:29,570
but they are very important now and very
very useful in especially development of

340
00:09:29,570 --> 00:09:29,580
very useful in especially development of

341
00:09:29,580 --> 00:09:32,030
very useful in especially development of
technology different technologies and

342
00:09:32,030 --> 00:09:32,040
technology different technologies and

343
00:09:32,040 --> 00:09:33,710
technology different technologies and
what are the nano materials

344
00:09:33,710 --> 00:09:33,720
what are the nano materials

345
00:09:33,720 --> 00:09:36,080
what are the nano materials
nanomaterials are crystalline compounds

346
00:09:36,080 --> 00:09:36,090
nanomaterials are crystalline compounds

347
00:09:36,090 --> 00:09:38,510
nanomaterials are crystalline compounds
with the crystals on the order of one to

348
00:09:38,510 --> 00:09:38,520
with the crystals on the order of one to

349
00:09:38,520 --> 00:09:42,190
with the crystals on the order of one to
ten nanometer what does that means

350
00:09:42,190 --> 00:09:42,200
ten nanometer what does that means

351
00:09:42,200 --> 00:09:45,260
ten nanometer what does that means
usually the crystals of the crystalline

352
00:09:45,260 --> 00:09:45,270
usually the crystals of the crystalline

353
00:09:45,270 --> 00:09:47,329
usually the crystals of the crystalline
compound solids are much much bigger

354
00:09:47,329 --> 00:09:47,339
compound solids are much much bigger

355
00:09:47,339 --> 00:09:50,090
compound solids are much much bigger
like considering the sodium chloride but

356
00:09:50,090 --> 00:09:50,100
like considering the sodium chloride but

357
00:09:50,100 --> 00:09:52,610
like considering the sodium chloride but
when you have that small these are very

358
00:09:52,610 --> 00:09:52,620
when you have that small these are very

359
00:09:52,620 --> 00:09:56,630
when you have that small these are very
very small crystals you know which are

360
00:09:56,630 --> 00:09:56,640
very small crystals you know which are

361
00:09:56,640 --> 00:09:58,730
very small crystals you know which are
crystals made of let's say hundred

362
00:09:58,730 --> 00:09:58,740
crystals made of let's say hundred

363
00:09:58,740 --> 00:10:00,650
crystals made of let's say hundred
hundred and twenty molecules and so on

364
00:10:00,650 --> 00:10:00,660
hundred and twenty molecules and so on

365
00:10:00,660 --> 00:10:03,440
hundred and twenty molecules and so on
and they have very very different

366
00:10:03,440 --> 00:10:03,450
and they have very very different

367
00:10:03,450 --> 00:10:06,070
and they have very very different
properties very different properties and

368
00:10:06,070 --> 00:10:06,080
properties very different properties and

369
00:10:06,080 --> 00:10:08,870
properties very different properties and
those different properties allow them to

370
00:10:08,870 --> 00:10:08,880
those different properties allow them to

371
00:10:08,880 --> 00:10:13,360
those different properties allow them to
be used you know apply for the

372
00:10:13,360 --> 00:10:13,370
be used you know apply for the

373
00:10:13,370 --> 00:10:17,329
be used you know apply for the
industrial or technological applications

374
00:10:17,329 --> 00:10:17,339
industrial or technological applications

375
00:10:17,339 --> 00:10:19,910
industrial or technological applications
again different applications and again

376
00:10:19,910 --> 00:10:19,920
again different applications and again

377
00:10:19,920 --> 00:10:21,829
again different applications and again
you see different properties and larger

378
00:10:21,829 --> 00:10:21,839
you see different properties and larger

379
00:10:21,839 --> 00:10:23,960
you see different properties and larger
crystalline materials so these are the

380
00:10:23,960 --> 00:10:23,970
crystalline materials so these are the

381
00:10:23,970 --> 00:10:28,100
crystalline materials so these are the
type of solids based on the force of

382
00:10:28,100 --> 00:10:28,110
type of solids based on the force of

383
00:10:28,110 --> 00:10:30,530
type of solids based on the force of
attraction that keeps them together hold

384
00:10:30,530 --> 00:10:30,540
attraction that keeps them together hold

385
00:10:30,540 --> 00:10:35,810
attraction that keeps them together hold
them together now the solids are also

386
00:10:35,810 --> 00:10:35,820
them together now the solids are also

387
00:10:35,820 --> 00:10:39,890
them together now the solids are also
classified into two according to the

388
00:10:39,890 --> 00:10:39,900
classified into two according to the

389
00:10:39,900 --> 00:10:43,190
classified into two according to the
structures or I should probably say the

390
00:10:43,190 --> 00:10:43,200
structures or I should probably say the

391
00:10:43,200 --> 00:10:46,100
structures or I should probably say the
arrangement of the molecules or the

392
00:10:46,100 --> 00:10:46,110
arrangement of the molecules or the

393
00:10:46,110 --> 00:10:49,010
arrangement of the molecules or the
atoms or the ions make the solids and

394
00:10:49,010 --> 00:10:49,020
atoms or the ions make the solids and

395
00:10:49,020 --> 00:10:52,640
atoms or the ions make the solids and
that is one is crystalline solid one

396
00:10:52,640 --> 00:10:52,650
that is one is crystalline solid one

397
00:10:52,650 --> 00:10:54,920
that is one is crystalline solid one
type are crystalline solids

398
00:10:54,920 --> 00:10:54,930
type are crystalline solids

399
00:10:54,930 --> 00:10:57,259
type are crystalline solids
the other are called amorphous solids

400
00:10:57,259 --> 00:10:57,269
the other are called amorphous solids

401
00:10:57,269 --> 00:11:00,739
the other are called amorphous solids
now crystalline solids are the solids in

402
00:11:00,739 --> 00:11:00,749
now crystalline solids are the solids in

403
00:11:00,749 --> 00:11:04,720
now crystalline solids are the solids in
which there is a very regular pattern of

404
00:11:04,720 --> 00:11:04,730
which there is a very regular pattern of

405
00:11:04,730 --> 00:11:07,850
which there is a very regular pattern of
arrangement of the units of the solids

406
00:11:07,850 --> 00:11:07,860
arrangement of the units of the solids

407
00:11:07,860 --> 00:11:10,519
arrangement of the units of the solids
very regular pattern what does that mean

408
00:11:10,519 --> 00:11:10,529
very regular pattern what does that mean

409
00:11:10,529 --> 00:11:12,169
very regular pattern what does that mean
that means like the distances between

410
00:11:12,169 --> 00:11:12,179
that means like the distances between

411
00:11:12,179 --> 00:11:15,559
that means like the distances between
them all the same and the position with

412
00:11:15,559 --> 00:11:15,569
them all the same and the position with

413
00:11:15,569 --> 00:11:17,359
them all the same and the position with
respect to each other all the same

414
00:11:17,359 --> 00:11:17,369
respect to each other all the same

415
00:11:17,369 --> 00:11:20,359
respect to each other all the same
they're very regular pattern and this

416
00:11:20,359 --> 00:11:20,369
they're very regular pattern and this

417
00:11:20,369 --> 00:11:22,759
they're very regular pattern and this
pattern repeats itself as a matter of

418
00:11:22,759 --> 00:11:22,769
pattern repeats itself as a matter of

419
00:11:22,769 --> 00:11:25,999
pattern repeats itself as a matter of
fact in the solid and they have a

420
00:11:25,999 --> 00:11:26,009
fact in the solid and they have a

421
00:11:26,009 --> 00:11:28,519
fact in the solid and they have a
particular structure in this

422
00:11:28,519 --> 00:11:28,529
particular structure in this

423
00:11:28,529 --> 00:11:30,530
particular structure in this
three-dimensional structure and those

424
00:11:30,530 --> 00:11:30,540
three-dimensional structure and those

425
00:11:30,540 --> 00:11:34,069
three-dimensional structure and those
are called the crystalline solids again

426
00:11:34,069 --> 00:11:34,079
are called the crystalline solids again

427
00:11:34,079 --> 00:11:38,059
are called the crystalline solids again
crystalline solids you can you can

428
00:11:38,059 --> 00:11:38,069
crystalline solids you can you can

429
00:11:38,069 --> 00:11:39,379
crystalline solids you can you can
determine the structures of those

430
00:11:39,379 --> 00:11:39,389
determine the structures of those

431
00:11:39,389 --> 00:11:42,530
determine the structures of those
crystalline sign crystalline solids very

432
00:11:42,530 --> 00:11:42,540
crystalline sign crystalline solids very

433
00:11:42,540 --> 00:11:44,569
crystalline sign crystalline solids very
effectively as a matter of fact now the

434
00:11:44,569 --> 00:11:44,579
effectively as a matter of fact now the

435
00:11:44,579 --> 00:11:47,090
effectively as a matter of fact now the
second is the amorphous solids amorphous

436
00:11:47,090 --> 00:11:47,100
second is the amorphous solids amorphous

437
00:11:47,100 --> 00:11:50,419
second is the amorphous solids amorphous
solids on the contrary have no regular

438
00:11:50,419 --> 00:11:50,429
solids on the contrary have no regular

439
00:11:50,429 --> 00:11:54,259
solids on the contrary have no regular
order of the units that makes the solids

440
00:11:54,259 --> 00:11:54,269
order of the units that makes the solids

441
00:11:54,269 --> 00:11:59,449
order of the units that makes the solids
they were just you know chaotic order is

442
00:11:59,449 --> 00:11:59,459
they were just you know chaotic order is

443
00:11:59,459 --> 00:12:03,199
they were just you know chaotic order is
present there and we can't really know

444
00:12:03,199 --> 00:12:03,209
present there and we can't really know

445
00:12:03,209 --> 00:12:06,290
present there and we can't really know
exactly the structure of the amorphous

446
00:12:06,290 --> 00:12:06,300
exactly the structure of the amorphous

447
00:12:06,300 --> 00:12:08,449
exactly the structure of the amorphous
solids because every amorphous solids

448
00:12:08,449 --> 00:12:08,459
solids because every amorphous solids

449
00:12:08,459 --> 00:12:10,639
solids because every amorphous solids
will have probably different

450
00:12:10,639 --> 00:12:10,649
will have probably different

451
00:12:10,649 --> 00:12:13,579
will have probably different
arrangements of the atoms or the

452
00:12:13,579 --> 00:12:13,589
arrangements of the atoms or the

453
00:12:13,589 --> 00:12:15,230
arrangements of the atoms or the
molecules or whatever the units made

454
00:12:15,230 --> 00:12:15,240
molecules or whatever the units made

455
00:12:15,240 --> 00:12:18,439
molecules or whatever the units made
them examples are for the crystalline

456
00:12:18,439 --> 00:12:18,449
them examples are for the crystalline

457
00:12:18,449 --> 00:12:22,369
them examples are for the crystalline
solid copper is a crystalline solids

458
00:12:22,369 --> 00:12:22,379
solid copper is a crystalline solids

459
00:12:22,379 --> 00:12:25,519
solid copper is a crystalline solids
right any metal Iren crystalline solid

460
00:12:25,519 --> 00:12:25,529
right any metal Iren crystalline solid

461
00:12:25,529 --> 00:12:28,249
right any metal Iren crystalline solid
sodium chloride crystalline solid it's

462
00:12:28,249 --> 00:12:28,259
sodium chloride crystalline solid it's

463
00:12:28,259 --> 00:12:31,249
sodium chloride crystalline solid it's
an ionic solid but crystalline solid ice

464
00:12:31,249 --> 00:12:31,259
an ionic solid but crystalline solid ice

465
00:12:31,259 --> 00:12:34,100
an ionic solid but crystalline solid ice
is a crystalline solid these are all

466
00:12:34,100 --> 00:12:34,110
is a crystalline solid these are all

467
00:12:34,110 --> 00:12:37,100
is a crystalline solid these are all
crystalline solids now what about the

468
00:12:37,100 --> 00:12:37,110
crystalline solids now what about the

469
00:12:37,110 --> 00:12:38,960
crystalline solids now what about the
amorphous solids example for the

470
00:12:38,960 --> 00:12:38,970
amorphous solids example for the

471
00:12:38,970 --> 00:12:44,660
amorphous solids example for the
amorphous solids are rubber and glass is

472
00:12:44,660 --> 00:12:44,670
amorphous solids are rubber and glass is

473
00:12:44,670 --> 00:12:48,730
amorphous solids are rubber and glass is
the amorphous solids as a matter of fact

474
00:12:48,730 --> 00:12:48,740
the amorphous solids as a matter of fact

475
00:12:48,740 --> 00:12:52,749
the amorphous solids as a matter of fact
now what is the difference can we simply

476
00:12:52,749 --> 00:12:52,759
now what is the difference can we simply

477
00:12:52,759 --> 00:12:55,519
now what is the difference can we simply
separate one from the other by a very

478
00:12:55,519 --> 00:12:55,529
separate one from the other by a very

479
00:12:55,529 --> 00:12:58,369
separate one from the other by a very
simple test for example in the lab if

480
00:12:58,369 --> 00:12:58,379
simple test for example in the lab if

481
00:12:58,379 --> 00:13:00,769
simple test for example in the lab if
you're given two solids and if they ask

482
00:13:00,769 --> 00:13:00,779
you're given two solids and if they ask

483
00:13:00,779 --> 00:13:03,679
you're given two solids and if they ask
you which one is the amorphous which one

484
00:13:03,679 --> 00:13:03,689
you which one is the amorphous which one

485
00:13:03,689 --> 00:13:05,360
you which one is the amorphous which one
is the crystalline one is amorphous one

486
00:13:05,360 --> 00:13:05,370
is the crystalline one is amorphous one

487
00:13:05,370 --> 00:13:07,429
is the crystalline one is amorphous one
crystalline what you have to look at the

488
00:13:07,429 --> 00:13:07,439
crystalline what you have to look at the

489
00:13:07,439 --> 00:13:08,230
crystalline what you have to look at the
melting

490
00:13:08,230 --> 00:13:08,240
melting

491
00:13:08,240 --> 00:13:11,800
melting
points the mountain points of

492
00:13:11,800 --> 00:13:11,810
points the mountain points of

493
00:13:11,810 --> 00:13:17,680
points the mountain points of
crystalline solids are sharp that simply

494
00:13:17,680 --> 00:13:17,690
crystalline solids are sharp that simply

495
00:13:17,690 --> 00:13:19,840
crystalline solids are sharp that simply
means for example if you take a

496
00:13:19,840 --> 00:13:19,850
means for example if you take a

497
00:13:19,850 --> 00:13:23,380
means for example if you take a
crystalline solid and he increases the

498
00:13:23,380 --> 00:13:23,390
crystalline solid and he increases the

499
00:13:23,390 --> 00:13:25,780
crystalline solid and he increases the
temperature of it he'll increase the

500
00:13:25,780 --> 00:13:25,790
temperature of it he'll increase the

501
00:13:25,790 --> 00:13:28,269
temperature of it he'll increase the
temperature and it will be solid until

502
00:13:28,269 --> 00:13:28,279
temperature and it will be solid until

503
00:13:28,279 --> 00:13:32,110
temperature and it will be solid until
it reaches to melting point when it

504
00:13:32,110 --> 00:13:32,120
it reaches to melting point when it

505
00:13:32,120 --> 00:13:33,699
it reaches to melting point when it
reaches to the melting point if you keep

506
00:13:33,699 --> 00:13:33,709
reaches to the melting point if you keep

507
00:13:33,709 --> 00:13:38,500
reaches to the melting point if you keep
heating it it will be liquid so actually

508
00:13:38,500 --> 00:13:38,510
heating it it will be liquid so actually

509
00:13:38,510 --> 00:13:41,290
heating it it will be liquid so actually
there's a sharp melting point at that

510
00:13:41,290 --> 00:13:41,300
there's a sharp melting point at that

511
00:13:41,300 --> 00:13:44,889
there's a sharp melting point at that
one temperature it will melt all if you

512
00:13:44,889 --> 00:13:44,899
one temperature it will melt all if you

513
00:13:44,899 --> 00:13:49,269
one temperature it will melt all if you
keep giving heat to that solid and but

514
00:13:49,269 --> 00:13:49,279
keep giving heat to that solid and but

515
00:13:49,279 --> 00:13:51,370
keep giving heat to that solid and but
if you have an amorphous solid like a

516
00:13:51,370 --> 00:13:51,380
if you have an amorphous solid like a

517
00:13:51,380 --> 00:13:55,660
if you have an amorphous solid like a
glass or rubber start heating it it will

518
00:13:55,660 --> 00:13:55,670
glass or rubber start heating it it will

519
00:13:55,670 --> 00:13:58,360
glass or rubber start heating it it will
simply get softer as you heat it softer

520
00:13:58,360 --> 00:13:58,370
simply get softer as you heat it softer

521
00:13:58,370 --> 00:14:01,420
simply get softer as you heat it softer
and softer and softer and softer finally

522
00:14:01,420 --> 00:14:01,430
and softer and softer and softer finally

523
00:14:01,430 --> 00:14:04,360
and softer and softer and softer finally
it may be you know liquids you can call

524
00:14:04,360 --> 00:14:04,370
it may be you know liquids you can call

525
00:14:04,370 --> 00:14:06,310
it may be you know liquids you can call
it so that means that the amorphous

526
00:14:06,310 --> 00:14:06,320
it so that means that the amorphous

527
00:14:06,320 --> 00:14:09,820
it so that means that the amorphous
solids do not have sharp melting points

528
00:14:09,820 --> 00:14:09,830
solids do not have sharp melting points

529
00:14:09,830 --> 00:14:13,030
solids do not have sharp melting points
like crystalline solids and they have a

530
00:14:13,030 --> 00:14:13,040
like crystalline solids and they have a

531
00:14:13,040 --> 00:14:15,760
like crystalline solids and they have a
range of mountain branch of mountain and

532
00:14:15,760 --> 00:14:15,770
range of mountain branch of mountain and

533
00:14:15,770 --> 00:14:18,280
range of mountain branch of mountain and
this is actually true for the robber and

534
00:14:18,280 --> 00:14:18,290
this is actually true for the robber and

535
00:14:18,290 --> 00:14:26,310
this is actually true for the robber and
true for the glass also - so again

536
00:14:26,310 --> 00:14:26,320
true for the glass also - so again

537
00:14:26,320 --> 00:14:28,690
true for the glass also - so again
crystalline solids have regular pattern

538
00:14:28,690 --> 00:14:28,700
crystalline solids have regular pattern

539
00:14:28,700 --> 00:14:31,720
crystalline solids have regular pattern
and they are of more interest to most

540
00:14:31,720 --> 00:14:31,730
and they are of more interest to most

541
00:14:31,730 --> 00:14:33,880
and they are of more interest to most
chemists actually we will talk about

542
00:14:33,880 --> 00:14:33,890
chemists actually we will talk about

543
00:14:33,890 --> 00:14:36,310
chemists actually we will talk about
more crystalline solids not the

544
00:14:36,310 --> 00:14:36,320
more crystalline solids not the

545
00:14:36,320 --> 00:14:38,650
more crystalline solids not the
amorphous solids because as I said very

546
00:14:38,650 --> 00:14:38,660
amorphous solids because as I said very

547
00:14:38,660 --> 00:14:40,810
amorphous solids because as I said very
difficult to study the amorphous solids

548
00:14:40,810 --> 00:14:40,820
difficult to study the amorphous solids

549
00:14:40,820 --> 00:14:43,780
difficult to study the amorphous solids
there's no regular pattern regular

550
00:14:43,780 --> 00:14:43,790
there's no regular pattern regular

551
00:14:43,790 --> 00:14:53,319
there's no regular pattern regular
structures and so on okay now we said

552
00:14:53,319 --> 00:14:53,329
structures and so on okay now we said

553
00:14:53,329 --> 00:14:56,230
structures and so on okay now we said
that the crystalline solids have very

554
00:14:56,230 --> 00:14:56,240
that the crystalline solids have very

555
00:14:56,240 --> 00:14:59,470
that the crystalline solids have very
regular pattern in three-dimensions

556
00:14:59,470 --> 00:14:59,480
regular pattern in three-dimensions

557
00:14:59,480 --> 00:15:01,300
regular pattern in three-dimensions
arrangement of their in terms of

558
00:15:01,300 --> 00:15:01,310
arrangement of their in terms of

559
00:15:01,310 --> 00:15:04,600
arrangement of their in terms of
arrangement of their atoms right and it

560
00:15:04,600 --> 00:15:04,610
arrangement of their atoms right and it

561
00:15:04,610 --> 00:15:09,550
arrangement of their atoms right and it
is sort of a in every crystalline solid

562
00:15:09,550 --> 00:15:09,560
is sort of a in every crystalline solid

563
00:15:09,560 --> 00:15:14,410
is sort of a in every crystalline solid
you can find a smallest unit which

564
00:15:14,410 --> 00:15:14,420
you can find a smallest unit which

565
00:15:14,420 --> 00:15:17,860
you can find a smallest unit which
repeats itself in the whole crystal

566
00:15:17,860 --> 00:15:17,870
repeats itself in the whole crystal

567
00:15:17,870 --> 00:15:19,630
repeats itself in the whole crystal
repeats itself in the or crystal that

568
00:15:19,630 --> 00:15:19,640
repeats itself in the or crystal that

569
00:15:19,640 --> 00:15:21,929
repeats itself in the or crystal that
simply means that all the

570
00:15:21,929 --> 00:15:21,939
simply means that all the

571
00:15:21,939 --> 00:15:25,319
simply means that all the
structural properties of the crystalline

572
00:15:25,319 --> 00:15:25,329
structural properties of the crystalline

573
00:15:25,329 --> 00:15:29,069
structural properties of the crystalline
solid can be obtained from that unit

574
00:15:29,069 --> 00:15:29,079
solid can be obtained from that unit

575
00:15:29,079 --> 00:15:32,309
solid can be obtained from that unit
smallest unit of the solid and that

576
00:15:32,309 --> 00:15:32,319
smallest unit of the solid and that

577
00:15:32,319 --> 00:15:36,359
smallest unit of the solid and that
smallest unit is called the unit cell of

578
00:15:36,359 --> 00:15:36,369
smallest unit is called the unit cell of

579
00:15:36,369 --> 00:15:39,960
smallest unit is called the unit cell of
the crystalline solid so the basis of

580
00:15:39,960 --> 00:15:39,970
the crystalline solid so the basis of

581
00:15:39,970 --> 00:15:42,419
the crystalline solid so the basis of
the repeating pattern is the unit cell

582
00:15:42,419 --> 00:15:42,429
the repeating pattern is the unit cell

583
00:15:42,429 --> 00:15:44,759
the repeating pattern is the unit cell
that means this this unit cell repeats

584
00:15:44,759 --> 00:15:44,769
that means this this unit cell repeats

585
00:15:44,769 --> 00:15:47,909
that means this this unit cell repeats
itself to get the crystalline solid the

586
00:15:47,909 --> 00:15:47,919
itself to get the crystalline solid the

587
00:15:47,919 --> 00:15:50,429
itself to get the crystalline solid the
whole crystalline solid the structure of

588
00:15:50,429 --> 00:15:50,439
whole crystalline solid the structure of

589
00:15:50,439 --> 00:15:53,429
whole crystalline solid the structure of
the crystalline solid is defined by the

590
00:15:53,429 --> 00:15:53,439
the crystalline solid is defined by the

591
00:15:53,439 --> 00:15:56,249
the crystalline solid is defined by the
size and shape of this unit cell so

592
00:15:56,249 --> 00:15:56,259
size and shape of this unit cell so

593
00:15:56,259 --> 00:15:58,319
size and shape of this unit cell so
these crystalline solids may be

594
00:15:58,319 --> 00:15:58,329
these crystalline solids may be

595
00:15:58,329 --> 00:16:00,149
these crystalline solids may be
different shapes and different sizes and

596
00:16:00,149 --> 00:16:00,159
different shapes and different sizes and

597
00:16:00,159 --> 00:16:03,329
different shapes and different sizes and
also the locations of the atoms within

598
00:16:03,329 --> 00:16:03,339
also the locations of the atoms within

599
00:16:03,339 --> 00:16:07,499
also the locations of the atoms within
the unit cell so the unit cell is the

600
00:16:07,499 --> 00:16:07,509
the unit cell so the unit cell is the

601
00:16:07,509 --> 00:16:13,529
the unit cell so the unit cell is the
smallest solids crystalline solid piece

602
00:16:13,529 --> 00:16:13,539
smallest solids crystalline solid piece

603
00:16:13,539 --> 00:16:16,409
smallest solids crystalline solid piece
which contains all the structural

604
00:16:16,409 --> 00:16:16,419
which contains all the structural

605
00:16:16,419 --> 00:16:19,919
which contains all the structural
properties of the solid what we mean

606
00:16:19,919 --> 00:16:19,929
properties of the solid what we mean

607
00:16:19,929 --> 00:16:21,869
properties of the solid what we mean
what I mean by the structural properties

608
00:16:21,869 --> 00:16:21,879
what I mean by the structural properties

609
00:16:21,879 --> 00:16:24,899
what I mean by the structural properties
for example the distances between the

610
00:16:24,899 --> 00:16:24,909
for example the distances between the

611
00:16:24,909 --> 00:16:31,589
for example the distances between the
atoms or some angles and the size of the

612
00:16:31,589 --> 00:16:31,599
atoms or some angles and the size of the

613
00:16:31,599 --> 00:16:34,739
atoms or some angles and the size of the
unit cells and positions of the atoms

614
00:16:34,739 --> 00:16:34,749
unit cells and positions of the atoms

615
00:16:34,749 --> 00:16:36,599
unit cells and positions of the atoms
with respect to each other different

616
00:16:36,599 --> 00:16:36,609
with respect to each other different

617
00:16:36,609 --> 00:16:43,829
with respect to each other different
kind of atoms and so on now when we talk

618
00:16:43,829 --> 00:16:43,839
kind of atoms and so on now when we talk

619
00:16:43,839 --> 00:16:46,829
kind of atoms and so on now when we talk
about crystalline solids we also talked

620
00:16:46,829 --> 00:16:46,839
about crystalline solids we also talked

621
00:16:46,839 --> 00:16:53,089
about crystalline solids we also talked
about lattice now letters simply means

622
00:16:53,089 --> 00:16:53,099
about lattice now letters simply means

623
00:16:53,099 --> 00:16:59,249
about lattice now letters simply means
the it shows you the arrangement of the

624
00:16:59,249 --> 00:16:59,259
the it shows you the arrangement of the

625
00:16:59,259 --> 00:17:01,409
the it shows you the arrangement of the
solid units in three dimensions

626
00:17:01,409 --> 00:17:01,419
solid units in three dimensions

627
00:17:01,419 --> 00:17:05,279
solid units in three dimensions
three dimensions and positions that

628
00:17:05,279 --> 00:17:05,289
three dimensions and positions that

629
00:17:05,289 --> 00:17:07,049
three dimensions and positions that
define the overall structure of the

630
00:17:07,049 --> 00:17:07,059
define the overall structure of the

631
00:17:07,059 --> 00:17:09,809
define the overall structure of the
crystalline compounds as you see here

632
00:17:09,809 --> 00:17:09,819
crystalline compounds as you see here

633
00:17:09,819 --> 00:17:10,799
crystalline compounds as you see here
are called

634
00:17:10,799 --> 00:17:10,809
are called

635
00:17:10,809 --> 00:17:12,779
are called
the lattice points those are called

636
00:17:12,779 --> 00:17:12,789
the lattice points those are called

637
00:17:12,789 --> 00:17:15,329
the lattice points those are called
lattice points now the lattice points

638
00:17:15,329 --> 00:17:15,339
lattice points now the lattice points

639
00:17:15,339 --> 00:17:18,860
lattice points now the lattice points
usually occupied by atoms or molecules

640
00:17:18,860 --> 00:17:18,870
usually occupied by atoms or molecules

641
00:17:18,870 --> 00:17:25,199
usually occupied by atoms or molecules
or ions but sometimes there is no atoms

642
00:17:25,199 --> 00:17:25,209
or ions but sometimes there is no atoms

643
00:17:25,209 --> 00:17:26,759
or ions but sometimes there is no atoms
or molecules in the lattice points but

644
00:17:26,759 --> 00:17:26,769
or molecules in the lattice points but

645
00:17:26,769 --> 00:17:29,940
or molecules in the lattice points but
usually they are simply occupied by the

646
00:17:29,940 --> 00:17:29,950
usually they are simply occupied by the

647
00:17:29,950 --> 00:17:33,200
usually they are simply occupied by the
atoms molecules or the ions

648
00:17:33,200 --> 00:17:33,210
atoms molecules or the ions

649
00:17:33,210 --> 00:17:35,030
atoms molecules or the ions
as a matter of fact now each lattice

650
00:17:35,030 --> 00:17:35,040
as a matter of fact now each lattice

651
00:17:35,040 --> 00:17:37,400
as a matter of fact now each lattice
points has an identical environment that

652
00:17:37,400 --> 00:17:37,410
points has an identical environment that

653
00:17:37,410 --> 00:17:39,830
points has an identical environment that
means that the positions of one lattice

654
00:17:39,830 --> 00:17:39,840
means that the positions of one lattice

655
00:17:39,840 --> 00:17:41,630
means that the positions of one lattice
point with respect to all the others are

656
00:17:41,630 --> 00:17:41,640
point with respect to all the others are

657
00:17:41,640 --> 00:17:45,650
point with respect to all the others are
the same now there define it says the

658
00:17:45,650 --> 00:17:45,660
the same now there define it says the

659
00:17:45,660 --> 00:17:47,810
the same now there define it says the
lettuce vectors connected the points and

660
00:17:47,810 --> 00:17:47,820
lettuce vectors connected the points and

661
00:17:47,820 --> 00:17:51,230
lettuce vectors connected the points and
define the unit cells now let's look at

662
00:17:51,230 --> 00:17:51,240
define the unit cells now let's look at

663
00:17:51,240 --> 00:17:54,310
define the unit cells now let's look at
what we mean here this is again a

664
00:17:54,310 --> 00:17:54,320
what we mean here this is again a

665
00:17:54,320 --> 00:17:59,990
what we mean here this is again a
three-dimensional lattice do we have a

666
00:17:59,990 --> 00:18:00,000
three-dimensional lattice do we have a

667
00:18:00,000 --> 00:18:01,790
three-dimensional lattice do we have a
three-dimensional lattice not really

668
00:18:01,790 --> 00:18:01,800
three-dimensional lattice not really

669
00:18:01,800 --> 00:18:03,380
three-dimensional lattice not really
you're usually the three-dimensional at

670
00:18:03,380 --> 00:18:03,390
you're usually the three-dimensional at

671
00:18:03,390 --> 00:18:06,440
you're usually the three-dimensional at
it but let's look at what we mean by

672
00:18:06,440 --> 00:18:06,450
it but let's look at what we mean by

673
00:18:06,450 --> 00:18:07,700
it but let's look at what we mean by
three dimensional two dimensional

674
00:18:07,700 --> 00:18:07,710
three dimensional two dimensional

675
00:18:07,710 --> 00:18:10,730
three dimensional two dimensional
lattice here you see again these are

676
00:18:10,730 --> 00:18:10,740
lattice here you see again these are

677
00:18:10,740 --> 00:18:13,910
lattice here you see again these are
called the lattice points and now in

678
00:18:13,910 --> 00:18:13,920
called the lattice points and now in

679
00:18:13,920 --> 00:18:16,430
called the lattice points and now in
this case they're actually occupied by

680
00:18:16,430 --> 00:18:16,440
this case they're actually occupied by

681
00:18:16,440 --> 00:18:20,780
this case they're actually occupied by
atoms occupied by atoms and the unit

682
00:18:20,780 --> 00:18:20,790
atoms occupied by atoms and the unit

683
00:18:20,790 --> 00:18:23,780
atoms occupied by atoms and the unit
cell of this is found by these vectors

684
00:18:23,780 --> 00:18:23,790
cell of this is found by these vectors

685
00:18:23,790 --> 00:18:26,270
cell of this is found by these vectors
see again we have a vector here and

686
00:18:26,270 --> 00:18:26,280
see again we have a vector here and

687
00:18:26,280 --> 00:18:28,730
see again we have a vector here and
vector there and that angle that means

688
00:18:28,730 --> 00:18:28,740
vector there and that angle that means

689
00:18:28,740 --> 00:18:31,610
vector there and that angle that means
that the unit cell in this case is this

690
00:18:31,610 --> 00:18:31,620
that the unit cell in this case is this

691
00:18:31,620 --> 00:18:34,280
that the unit cell in this case is this
shape right here that is the unit cell

692
00:18:34,280 --> 00:18:34,290
shape right here that is the unit cell

693
00:18:34,290 --> 00:18:38,150
shape right here that is the unit cell
and and we have the angle here and we

694
00:18:38,150 --> 00:18:38,160
and and we have the angle here and we

695
00:18:38,160 --> 00:18:40,520
and and we have the angle here and we
have the distances a and B as a matter

696
00:18:40,520 --> 00:18:40,530
have the distances a and B as a matter

697
00:18:40,530 --> 00:18:43,640
have the distances a and B as a matter
of fact and in this case the unit cell

698
00:18:43,640 --> 00:18:43,650
of fact and in this case the unit cell

699
00:18:43,650 --> 00:18:46,640
of fact and in this case the unit cell
is again here like this this part is the

700
00:18:46,640 --> 00:18:46,650
is again here like this this part is the

701
00:18:46,650 --> 00:18:49,100
is again here like this this part is the
unit cells and that is the repeating

702
00:18:49,100 --> 00:18:49,110
unit cells and that is the repeating

703
00:18:49,110 --> 00:18:51,200
unit cells and that is the repeating
unit in fact if you take that and put it

704
00:18:51,200 --> 00:18:51,210
unit in fact if you take that and put it

705
00:18:51,210 --> 00:18:52,730
unit in fact if you take that and put it
on the top of each other you get the

706
00:18:52,730 --> 00:18:52,740
on the top of each other you get the

707
00:18:52,740 --> 00:18:54,680
on the top of each other you get the
whole things over here and this is again

708
00:18:54,680 --> 00:18:54,690
whole things over here and this is again

709
00:18:54,690 --> 00:18:57,560
whole things over here and this is again
the unit cell and unit cell is a little

710
00:18:57,560 --> 00:18:57,570
the unit cell and unit cell is a little

711
00:18:57,570 --> 00:19:00,110
the unit cell and unit cell is a little
bit different in hexagonal case and this

712
00:19:00,110 --> 00:19:00,120
bit different in hexagonal case and this

713
00:19:00,120 --> 00:19:02,630
bit different in hexagonal case and this
is the rhombic unit cells so this is

714
00:19:02,630 --> 00:19:02,640
is the rhombic unit cells so this is

715
00:19:02,640 --> 00:19:05,770
is the rhombic unit cells so this is
simply there is a gain very close

716
00:19:05,770 --> 00:19:05,780
simply there is a gain very close

717
00:19:05,780 --> 00:19:08,870
simply there is a gain very close
relationship between the lattice points

718
00:19:08,870 --> 00:19:08,880
relationship between the lattice points

719
00:19:08,880 --> 00:19:12,800
relationship between the lattice points
and the positions of the atoms molecules

720
00:19:12,800 --> 00:19:12,810
and the positions of the atoms molecules

721
00:19:12,810 --> 00:19:15,740
and the positions of the atoms molecules
or the ions that makes the solid

722
00:19:15,740 --> 00:19:15,750
or the ions that makes the solid

723
00:19:15,750 --> 00:19:21,500
or the ions that makes the solid
crystalline solids right it simply tells

724
00:19:21,500 --> 00:19:21,510
crystalline solids right it simply tells

725
00:19:21,510 --> 00:19:22,850
crystalline solids right it simply tells
you information about how the

726
00:19:22,850 --> 00:19:22,860
you information about how the

727
00:19:22,860 --> 00:19:26,600
you information about how the
arrangements of those in the solids now

728
00:19:26,600 --> 00:19:26,610
arrangements of those in the solids now

729
00:19:26,610 --> 00:19:29,230
arrangements of those in the solids now
let's look at the three dimensional

730
00:19:29,230 --> 00:19:29,240
let's look at the three dimensional

731
00:19:29,240 --> 00:19:31,850
let's look at the three dimensional
crystals and three dimensional lattices

732
00:19:31,850 --> 00:19:31,860
crystals and three dimensional lattices

733
00:19:31,860 --> 00:19:34,220
crystals and three dimensional lattices
and in three dimensional lattices

734
00:19:34,220 --> 00:19:34,230
and in three dimensional lattices

735
00:19:34,230 --> 00:19:38,420
and in three dimensional lattices
actually we have three dimensional unit

736
00:19:38,420 --> 00:19:38,430
actually we have three dimensional unit

737
00:19:38,430 --> 00:19:42,020
actually we have three dimensional unit
cells unit cells and the unit cells the

738
00:19:42,020 --> 00:19:42,030
cells unit cells and the unit cells the

739
00:19:42,030 --> 00:19:43,670
cells unit cells and the unit cells the
these are simply called the primitive

740
00:19:43,670 --> 00:19:43,680
these are simply called the primitive

741
00:19:43,680 --> 00:19:45,980
these are simply called the primitive
unit cells there are only seven types of

742
00:19:45,980 --> 00:19:45,990
unit cells there are only seven types of

743
00:19:45,990 --> 00:19:46,650
unit cells there are only seven types of
those

744
00:19:46,650 --> 00:19:46,660
those

745
00:19:46,660 --> 00:19:48,660
those
seven basic two-dimensional lattices you

746
00:19:48,660 --> 00:19:48,670
seven basic two-dimensional lattices you

747
00:19:48,670 --> 00:19:51,240
seven basic two-dimensional lattices you
see again cubic tetragonal orthorhombic

748
00:19:51,240 --> 00:19:51,250
see again cubic tetragonal orthorhombic

749
00:19:51,250 --> 00:19:54,090
see again cubic tetragonal orthorhombic
rhombohedral hexagonal monoclinic and

750
00:19:54,090 --> 00:19:54,100
rhombohedral hexagonal monoclinic and

751
00:19:54,100 --> 00:19:54,480
rhombohedral hexagonal monoclinic and
trackless

752
00:19:54,480 --> 00:19:54,490
trackless

753
00:19:54,490 --> 00:19:56,490
trackless
these are the special name now if you

754
00:19:56,490 --> 00:19:56,500
these are the special name now if you

755
00:19:56,500 --> 00:19:59,100
these are the special name now if you
just ask me do you you have to remember

756
00:19:59,100 --> 00:19:59,110
just ask me do you you have to remember

757
00:19:59,110 --> 00:19:59,640
just ask me do you you have to remember
these

758
00:19:59,640 --> 00:19:59,650
these

759
00:19:59,650 --> 00:20:01,950
these
I guess the cubic is the most important

760
00:20:01,950 --> 00:20:01,960
I guess the cubic is the most important

761
00:20:01,960 --> 00:20:03,960
I guess the cubic is the most important
probably you can remember these but the

762
00:20:03,960 --> 00:20:03,970
probably you can remember these but the

763
00:20:03,970 --> 00:20:05,760
probably you can remember these but the
others are little bit poor difficult as

764
00:20:05,760 --> 00:20:05,770
others are little bit poor difficult as

765
00:20:05,770 --> 00:20:08,610
others are little bit poor difficult as
a matter of fact now what are these this

766
00:20:08,610 --> 00:20:08,620
a matter of fact now what are these this

767
00:20:08,620 --> 00:20:14,480
a matter of fact now what are these this
is simply a coupe right and then the

768
00:20:14,480 --> 00:20:14,490
is simply a coupe right and then the

769
00:20:14,490 --> 00:20:18,180
is simply a coupe right and then the
actually the a B and C are equal right

770
00:20:18,180 --> 00:20:18,190
actually the a B and C are equal right

771
00:20:18,190 --> 00:20:20,700
actually the a B and C are equal right
and the angles are equal at 90 degrees

772
00:20:20,700 --> 00:20:20,710
and the angles are equal at 90 degrees

773
00:20:20,710 --> 00:20:24,240
and the angles are equal at 90 degrees
and this one is tetragonal tetragonal is

774
00:20:24,240 --> 00:20:24,250
and this one is tetragonal tetragonal is

775
00:20:24,250 --> 00:20:26,190
and this one is tetragonal tetragonal is
simply a is equal to b but b is not

776
00:20:26,190 --> 00:20:26,200
simply a is equal to b but b is not

777
00:20:26,200 --> 00:20:29,130
simply a is equal to b but b is not
equal to c all the angles are equal this

778
00:20:29,130 --> 00:20:29,140
equal to c all the angles are equal this

779
00:20:29,140 --> 00:20:33,660
equal to c all the angles are equal this
is in turkish what or in english yes it

780
00:20:33,660 --> 00:20:33,670
is in turkish what or in english yes it

781
00:20:33,670 --> 00:20:36,540
is in turkish what or in english yes it
is a square prism right it's a square

782
00:20:36,540 --> 00:20:36,550
is a square prism right it's a square

783
00:20:36,550 --> 00:20:38,520
is a square prism right it's a square
prism nothing but just a square prism

784
00:20:38,520 --> 00:20:38,530
prism nothing but just a square prism

785
00:20:38,530 --> 00:20:41,250
prism nothing but just a square prism
now remember these are the lattice

786
00:20:41,250 --> 00:20:41,260
now remember these are the lattice

787
00:20:41,260 --> 00:20:44,850
now remember these are the lattice
points here right so remember this will

788
00:20:44,850 --> 00:20:44,860
points here right so remember this will

789
00:20:44,860 --> 00:20:46,170
points here right so remember this will
be in three dimension you will have a

790
00:20:46,170 --> 00:20:46,180
be in three dimension you will have a

791
00:20:46,180 --> 00:20:47,790
be in three dimension you will have a
lot of those put together side by side

792
00:20:47,790 --> 00:20:47,800
lot of those put together side by side

793
00:20:47,800 --> 00:20:50,400
lot of those put together side by side
to get the lattice and the crystalline

794
00:20:50,400 --> 00:20:50,410
to get the lattice and the crystalline

795
00:20:50,410 --> 00:20:51,000
to get the lattice and the crystalline
solid

796
00:20:51,000 --> 00:20:51,010
solid

797
00:20:51,010 --> 00:20:53,160
solid
now this one is orthorhombic they are

798
00:20:53,160 --> 00:20:53,170
now this one is orthorhombic they are

799
00:20:53,170 --> 00:20:55,290
now this one is orthorhombic they are
not all equal 90 degrees what is this

800
00:20:55,290 --> 00:20:55,300
not all equal 90 degrees what is this

801
00:20:55,300 --> 00:20:58,620
not all equal 90 degrees what is this
this is a rectangular prism rectangular

802
00:20:58,620 --> 00:20:58,630
this is a rectangular prism rectangular

803
00:20:58,630 --> 00:21:00,920
this is a rectangular prism rectangular
prism now the others actually

804
00:21:00,920 --> 00:21:00,930
prism now the others actually

805
00:21:00,930 --> 00:21:03,960
prism now the others actually
rhombohedral there you take the cube and

806
00:21:03,960 --> 00:21:03,970
rhombohedral there you take the cube and

807
00:21:03,970 --> 00:21:05,850
rhombohedral there you take the cube and
then press it in one directions you

808
00:21:05,850 --> 00:21:05,860
then press it in one directions you

809
00:21:05,860 --> 00:21:08,550
then press it in one directions you
change the angle here and you get the

810
00:21:08,550 --> 00:21:08,560
change the angle here and you get the

811
00:21:08,560 --> 00:21:12,660
change the angle here and you get the
rhombohedral now hexagonal is a little

812
00:21:12,660 --> 00:21:12,670
rhombohedral now hexagonal is a little

813
00:21:12,670 --> 00:21:15,150
rhombohedral now hexagonal is a little
bit different actually the hexagonal

814
00:21:15,150 --> 00:21:15,160
bit different actually the hexagonal

815
00:21:15,160 --> 00:21:19,770
bit different actually the hexagonal
unit cell usually is given in this

816
00:21:19,770 --> 00:21:19,780
unit cell usually is given in this

817
00:21:19,780 --> 00:21:29,070
unit cell usually is given in this
fashion

818
00:21:29,070 --> 00:21:29,080

819
00:21:29,080 --> 00:21:36,870
this is the hexagonal prism like this

820
00:21:36,870 --> 00:21:36,880
this is the hexagonal prism like this

821
00:21:36,880 --> 00:21:42,610
this is the hexagonal prism like this
but the hexagonal unit cell given here

822
00:21:42,610 --> 00:21:42,620
but the hexagonal unit cell given here

823
00:21:42,620 --> 00:21:44,710
but the hexagonal unit cell given here
is one third office

824
00:21:44,710 --> 00:21:44,720
is one third office

825
00:21:44,720 --> 00:21:48,520
is one third office
this one is one third of this and that

826
00:21:48,520 --> 00:21:48,530
this one is one third of this and that

827
00:21:48,530 --> 00:21:51,399
this one is one third of this and that
means that okay if you take that there

828
00:21:51,399 --> 00:21:51,409
means that okay if you take that there

829
00:21:51,409 --> 00:21:56,830
means that okay if you take that there
and you connect this and that and that

830
00:21:56,830 --> 00:21:56,840
and you connect this and that and that

831
00:21:56,840 --> 00:22:00,779
and you connect this and that and that
here we see again same things is true

832
00:22:00,779 --> 00:22:00,789
here we see again same things is true

833
00:22:00,789 --> 00:22:07,320
here we see again same things is true
here like this each of these prisms is

834
00:22:07,320 --> 00:22:07,330
here like this each of these prisms is

835
00:22:07,330 --> 00:22:10,240
here like this each of these prisms is
part of the hexagonal unit cell that

836
00:22:10,240 --> 00:22:10,250
part of the hexagonal unit cell that

837
00:22:10,250 --> 00:22:12,880
part of the hexagonal unit cell that
part if you take three of those and put

838
00:22:12,880 --> 00:22:12,890
part if you take three of those and put

839
00:22:12,890 --> 00:22:16,230
part if you take three of those and put
together you get this this is the

840
00:22:16,230 --> 00:22:16,240
together you get this this is the

841
00:22:16,240 --> 00:22:19,419
together you get this this is the
hexagonal prism again now remember you

842
00:22:19,419 --> 00:22:19,429
hexagonal prism again now remember you

843
00:22:19,429 --> 00:22:23,490
hexagonal prism again now remember you
have the lattice points and also the

844
00:22:23,490 --> 00:22:23,500
have the lattice points and also the

845
00:22:23,500 --> 00:22:30,600
have the lattice points and also the
atoms or molecules whatever the lattice

846
00:22:30,600 --> 00:22:30,610
atoms or molecules whatever the lattice

847
00:22:30,610 --> 00:22:33,460
atoms or molecules whatever the lattice
crystalline solid is made of that is the

848
00:22:33,460 --> 00:22:33,470
crystalline solid is made of that is the

849
00:22:33,470 --> 00:22:36,610
crystalline solid is made of that is the
hexagonal prism actually and that is one

850
00:22:36,610 --> 00:22:36,620
hexagonal prism actually and that is one

851
00:22:36,620 --> 00:22:41,649
hexagonal prism actually and that is one
third of that is the this unit cell over

852
00:22:41,649 --> 00:22:41,659
third of that is the this unit cell over

853
00:22:41,659 --> 00:22:43,779
third of that is the this unit cell over
here hexagonal unit cell monoclinic

854
00:22:43,779 --> 00:22:43,789
here hexagonal unit cell monoclinic

855
00:22:43,789 --> 00:22:47,770
here hexagonal unit cell monoclinic
again the a B and C are all different

856
00:22:47,770 --> 00:22:47,780
again the a B and C are all different

857
00:22:47,780 --> 00:22:50,590
again the a B and C are all different
and angles 90 degrees one of them the

858
00:22:50,590 --> 00:22:50,600
and angles 90 degrees one of them the

859
00:22:50,600 --> 00:22:52,029
and angles 90 degrees one of them the
other one is not ninety degrees that

860
00:22:52,029 --> 00:22:52,039
other one is not ninety degrees that

861
00:22:52,039 --> 00:22:55,630
other one is not ninety degrees that
means you take that or two rhombic and

862
00:22:55,630 --> 00:22:55,640
means you take that or two rhombic and

863
00:22:55,640 --> 00:22:57,789
means you take that or two rhombic and
then press it a little bit one side you

864
00:22:57,789 --> 00:22:57,799
then press it a little bit one side you

865
00:22:57,799 --> 00:23:02,190
then press it a little bit one side you
get done triclinic is all angles and the

866
00:23:02,190 --> 00:23:02,200
get done triclinic is all angles and the

867
00:23:02,200 --> 00:23:07,560
get done triclinic is all angles and the
edges are different from one another now

868
00:23:07,560 --> 00:23:07,570
edges are different from one another now

869
00:23:07,570 --> 00:23:11,580
edges are different from one another now
we will these are actually called

870
00:23:11,580 --> 00:23:11,590
we will these are actually called

871
00:23:11,590 --> 00:23:14,380
we will these are actually called
primitive unit cells that means that

872
00:23:14,380 --> 00:23:14,390
primitive unit cells that means that

873
00:23:14,390 --> 00:23:18,039
primitive unit cells that means that
only the corners are occupied by atoms

874
00:23:18,039 --> 00:23:18,049
only the corners are occupied by atoms

875
00:23:18,049 --> 00:23:20,860
only the corners are occupied by atoms
or ions or molecules but you can also

876
00:23:20,860 --> 00:23:20,870
or ions or molecules but you can also

877
00:23:20,870 --> 00:23:24,070
or ions or molecules but you can also
have simply atoms or molecules or ions

878
00:23:24,070 --> 00:23:24,080
have simply atoms or molecules or ions

879
00:23:24,080 --> 00:23:28,060
have simply atoms or molecules or ions
in the center of these unit cells or

880
00:23:28,060 --> 00:23:28,070
in the center of these unit cells or

881
00:23:28,070 --> 00:23:30,520
in the center of these unit cells or
maybe in the center of the faces or

882
00:23:30,520 --> 00:23:30,530
maybe in the center of the faces or

883
00:23:30,530 --> 00:23:33,520
maybe in the center of the faces or
maybe in the center of the edges all of

884
00:23:33,520 --> 00:23:33,530
maybe in the center of the edges all of

885
00:23:33,530 --> 00:23:36,480
maybe in the center of the edges all of
those are possible and when you have all

886
00:23:36,480 --> 00:23:36,490
those are possible and when you have all

887
00:23:36,490 --> 00:23:40,680
those are possible and when you have all
those unit cells total number of

888
00:23:40,680 --> 00:23:40,690
those unit cells total number of

889
00:23:40,690 --> 00:23:43,380
those unit cells total number of
ourselves in nature that we find is 32

890
00:23:43,380 --> 00:23:43,390
ourselves in nature that we find is 32

891
00:23:43,390 --> 00:23:47,040
ourselves in nature that we find is 32
there are 32 different types of unicel

892
00:23:47,040 --> 00:23:47,050
there are 32 different types of unicel

893
00:23:47,050 --> 00:23:50,580
there are 32 different types of unicel
for crystalline solids in nature and all

894
00:23:50,580 --> 00:23:50,590
for crystalline solids in nature and all

895
00:23:50,590 --> 00:23:52,140
for crystalline solids in nature and all
of those are derived from these

896
00:23:52,140 --> 00:23:52,150
of those are derived from these

897
00:23:52,150 --> 00:23:54,210
of those are derived from these
primitive seven primitive unit cells

898
00:23:54,210 --> 00:23:54,220
primitive seven primitive unit cells

899
00:23:54,220 --> 00:23:57,600
primitive seven primitive unit cells
seven primitive unit cells now we will

900
00:23:57,600 --> 00:23:57,610
seven primitive unit cells now we will

901
00:23:57,610 --> 00:24:00,180
seven primitive unit cells now we will
more concentrate on the cubic unit cell

902
00:24:00,180 --> 00:24:00,190
more concentrate on the cubic unit cell

903
00:24:00,190 --> 00:24:04,680
more concentrate on the cubic unit cell
and also three different form of these

904
00:24:04,680 --> 00:24:04,690
and also three different form of these

905
00:24:04,690 --> 00:24:07,110
and also three different form of these
cubic unit cell this one is simply

906
00:24:07,110 --> 00:24:07,120
cubic unit cell this one is simply

907
00:24:07,120 --> 00:24:07,620
cubic unit cell this one is simply
called

908
00:24:07,620 --> 00:24:07,630
called

909
00:24:07,630 --> 00:24:10,770
called
primitive cubic unit cells remember this

910
00:24:10,770 --> 00:24:10,780
primitive cubic unit cells remember this

911
00:24:10,780 --> 00:24:14,430
primitive cubic unit cells remember this
is just a cube again now this one is we

912
00:24:14,430 --> 00:24:14,440
is just a cube again now this one is we

913
00:24:14,440 --> 00:24:17,160
is just a cube again now this one is we
have the lattice points here and the

914
00:24:17,160 --> 00:24:17,170
have the lattice points here and the

915
00:24:17,170 --> 00:24:19,890
have the lattice points here and the
atoms and we also have one in the center

916
00:24:19,890 --> 00:24:19,900
atoms and we also have one in the center

917
00:24:19,900 --> 00:24:22,740
atoms and we also have one in the center
here and this may be a lattice point may

918
00:24:22,740 --> 00:24:22,750
here and this may be a lattice point may

919
00:24:22,750 --> 00:24:24,780
here and this may be a lattice point may
not be at it doesn't have to be a legend

920
00:24:24,780 --> 00:24:24,790
not be at it doesn't have to be a legend

921
00:24:24,790 --> 00:24:26,760
not be at it doesn't have to be a legend
but there is a molecule or atom there in

922
00:24:26,760 --> 00:24:26,770
but there is a molecule or atom there in

923
00:24:26,770 --> 00:24:28,830
but there is a molecule or atom there in
the middle and that is the body centered

924
00:24:28,830 --> 00:24:28,840
the middle and that is the body centered

925
00:24:28,840 --> 00:24:31,290
the middle and that is the body centered
cubic unit cell and this one is we have

926
00:24:31,290 --> 00:24:31,300
cubic unit cell and this one is we have

927
00:24:31,300 --> 00:24:35,310
cubic unit cell and this one is we have
on the centre of the faces six faces and

928
00:24:35,310 --> 00:24:35,320
on the centre of the faces six faces and

929
00:24:35,320 --> 00:24:38,250
on the centre of the faces six faces and
this is the face centered unit cell so

930
00:24:38,250 --> 00:24:38,260
this is the face centered unit cell so

931
00:24:38,260 --> 00:24:40,710
this is the face centered unit cell so
we will mostly talk about these three

932
00:24:40,710 --> 00:24:40,720
we will mostly talk about these three

933
00:24:40,720 --> 00:24:43,290
we will mostly talk about these three
types of unit cells and in our

934
00:24:43,290 --> 00:24:43,300
types of unit cells and in our

935
00:24:43,300 --> 00:24:45,480
types of unit cells and in our
calculations and so on we will use these

936
00:24:45,480 --> 00:24:45,490
calculations and so on we will use these

937
00:24:45,490 --> 00:24:51,210
calculations and so on we will use these
and these are the unit cells of metals

938
00:24:51,210 --> 00:24:51,220
and these are the unit cells of metals

939
00:24:51,220 --> 00:24:53,940
and these are the unit cells of metals
usually solid metals because the solid

940
00:24:53,940 --> 00:24:53,950
usually solid metals because the solid

941
00:24:53,950 --> 00:24:56,760
usually solid metals because the solid
metals can be considered as the same

942
00:24:56,760 --> 00:24:56,770
metals can be considered as the same

943
00:24:56,770 --> 00:25:01,620
metals can be considered as the same
size Phares right so those metal ions

944
00:25:01,620 --> 00:25:01,630
size Phares right so those metal ions

945
00:25:01,630 --> 00:25:03,630
size Phares right so those metal ions
simply occupy the lattice points and

946
00:25:03,630 --> 00:25:03,640
simply occupy the lattice points and

947
00:25:03,640 --> 00:25:06,450
simply occupy the lattice points and
they simply touch each other as we will

948
00:25:06,450 --> 00:25:06,460
they simply touch each other as we will

949
00:25:06,460 --> 00:25:12,570
they simply touch each other as we will
see in later slides this is again motifs

950
00:25:12,570 --> 00:25:12,580
see in later slides this is again motifs

951
00:25:12,580 --> 00:25:15,360
see in later slides this is again motifs
it simply means in those unit lattice

952
00:25:15,360 --> 00:25:15,370
it simply means in those unit lattice

953
00:25:15,370 --> 00:25:17,790
it simply means in those unit lattice
points you may have an atom you may have

954
00:25:17,790 --> 00:25:17,800
points you may have an atom you may have

955
00:25:17,800 --> 00:25:20,780
points you may have an atom you may have
an iron ore you may have a molecule

956
00:25:20,780 --> 00:25:20,790
an iron ore you may have a molecule

957
00:25:20,790 --> 00:25:24,530
an iron ore you may have a molecule
right and those are whatever simply

958
00:25:24,530 --> 00:25:24,540
right and those are whatever simply

959
00:25:24,540 --> 00:25:27,030
right and those are whatever simply
occupies those lattice points are called

960
00:25:27,030 --> 00:25:27,040
occupies those lattice points are called

961
00:25:27,040 --> 00:25:28,980
occupies those lattice points are called
they don't have to be lattice points

962
00:25:28,980 --> 00:25:28,990
they don't have to be lattice points

963
00:25:28,990 --> 00:25:32,150
they don't have to be lattice points
actually but they're called they can be

964
00:25:32,150 --> 00:25:32,160
actually but they're called they can be

965
00:25:32,160 --> 00:25:34,800
actually but they're called they can be
not in the lattice points for example in

966
00:25:34,800 --> 00:25:34,810
not in the lattice points for example in

967
00:25:34,810 --> 00:25:36,240
not in the lattice points for example in
this case these are the lattice points

968
00:25:36,240 --> 00:25:36,250
this case these are the lattice points

969
00:25:36,250 --> 00:25:39,600
this case these are the lattice points
here but the motive or the unit of the

970
00:25:39,600 --> 00:25:39,610
here but the motive or the unit of the

971
00:25:39,610 --> 00:25:42,920
here but the motive or the unit of the
solids is this those two atoms there and

972
00:25:42,920 --> 00:25:42,930
solids is this those two atoms there and

973
00:25:42,930 --> 00:25:45,510
solids is this those two atoms there and
that's what we call motives again but

974
00:25:45,510 --> 00:25:45,520
that's what we call motives again but

975
00:25:45,520 --> 00:25:49,860
that's what we call motives again but
the ones we will consider are mostly the

976
00:25:49,860 --> 00:25:49,870
the ones we will consider are mostly the

977
00:25:49,870 --> 00:25:52,800
the ones we will consider are mostly the
atoms or the molecules ions occupies the

978
00:25:52,800 --> 00:25:52,810
atoms or the molecules ions occupies the

979
00:25:52,810 --> 00:25:56,570
atoms or the molecules ions occupies the
lattice points

980
00:25:56,570 --> 00:25:56,580

981
00:25:56,580 --> 00:26:01,830
now metallic structures again metallic

982
00:26:01,830 --> 00:26:01,840
now metallic structures again metallic

983
00:26:01,840 --> 00:26:04,530
now metallic structures again metallic
structures easily be understood in terms

984
00:26:04,530 --> 00:26:04,540
structures easily be understood in terms

985
00:26:04,540 --> 00:26:08,880
structures easily be understood in terms
of packing of spheres actually packing

986
00:26:08,880 --> 00:26:08,890
of packing of spheres actually packing

987
00:26:08,890 --> 00:26:12,030
of packing of spheres actually packing
of spheres and if we consider three

988
00:26:12,030 --> 00:26:12,040
of spheres and if we consider three

989
00:26:12,040 --> 00:26:15,810
of spheres and if we consider three
different structures cubic body-centered

990
00:26:15,810 --> 00:26:15,820
different structures cubic body-centered

991
00:26:15,820 --> 00:26:18,900
different structures cubic body-centered
cubic and face centered cubic lattices

992
00:26:18,900 --> 00:26:18,910
cubic and face centered cubic lattices

993
00:26:18,910 --> 00:26:22,380
cubic and face centered cubic lattices
and these are the unit cells the metal

994
00:26:22,380 --> 00:26:22,390
and these are the unit cells the metal

995
00:26:22,390 --> 00:26:26,340
and these are the unit cells the metal
atoms Fairs will occupy the corners of

996
00:26:26,340 --> 00:26:26,350
atoms Fairs will occupy the corners of

997
00:26:26,350 --> 00:26:30,660
atoms Fairs will occupy the corners of
these and if we look at the space

998
00:26:30,660 --> 00:26:30,670
these and if we look at the space

999
00:26:30,670 --> 00:26:36,210
these and if we look at the space
filling type unit cells letters for the

1000
00:26:36,210 --> 00:26:36,220
filling type unit cells letters for the

1001
00:26:36,220 --> 00:26:39,330
filling type unit cells letters for the
primitive unit cell again simple cubic

1002
00:26:39,330 --> 00:26:39,340
primitive unit cell again simple cubic

1003
00:26:39,340 --> 00:26:41,730
primitive unit cell again simple cubic
unit cell it would look like this what

1004
00:26:41,730 --> 00:26:41,740
unit cell it would look like this what

1005
00:26:41,740 --> 00:26:43,530
unit cell it would look like this what
does that mean that means we have a

1006
00:26:43,530 --> 00:26:43,540
does that mean that means we have a

1007
00:26:43,540 --> 00:26:47,790
does that mean that means we have a
sphere actually a metal atom in this

1008
00:26:47,790 --> 00:26:47,800
sphere actually a metal atom in this

1009
00:26:47,800 --> 00:26:49,740
sphere actually a metal atom in this
corner that corner that corner eight

1010
00:26:49,740 --> 00:26:49,750
corner that corner that corner eight

1011
00:26:49,750 --> 00:26:54,030
corner that corner that corner eight
corners and all of those four metal

1012
00:26:54,030 --> 00:26:54,040
corners and all of those four metal

1013
00:26:54,040 --> 00:26:56,730
corners and all of those four metal
atoms are touching each other they are

1014
00:26:56,730 --> 00:26:56,740
atoms are touching each other they are

1015
00:26:56,740 --> 00:26:58,890
atoms are touching each other they are
simply touching each other and the same

1016
00:26:58,890 --> 00:26:58,900
simply touching each other and the same

1017
00:26:58,900 --> 00:27:00,780
simply touching each other and the same
thing is true over here now when you

1018
00:27:00,780 --> 00:27:00,790
thing is true over here now when you

1019
00:27:00,790 --> 00:27:03,120
thing is true over here now when you
have a body centered cubic unit cell you

1020
00:27:03,120 --> 00:27:03,130
have a body centered cubic unit cell you

1021
00:27:03,130 --> 00:27:07,170
have a body centered cubic unit cell you
have simply the metal atoms at the

1022
00:27:07,170 --> 00:27:07,180
have simply the metal atoms at the

1023
00:27:07,180 --> 00:27:11,190
have simply the metal atoms at the
corner here four up four down and one in

1024
00:27:11,190 --> 00:27:11,200
corner here four up four down and one in

1025
00:27:11,200 --> 00:27:14,300
corner here four up four down and one in
the middle of the cube and this is the

1026
00:27:14,300 --> 00:27:14,310
the middle of the cube and this is the

1027
00:27:14,310 --> 00:27:17,880
the middle of the cube and this is the
unit cell actually for the body centered

1028
00:27:17,880 --> 00:27:17,890
unit cell actually for the body centered

1029
00:27:17,890 --> 00:27:22,230
unit cell actually for the body centered
cubic structures and face centered wise

1030
00:27:22,230 --> 00:27:22,240
cubic structures and face centered wise

1031
00:27:22,240 --> 00:27:25,170
cubic structures and face centered wise
we have again at the corners and then we

1032
00:27:25,170 --> 00:27:25,180
we have again at the corners and then we

1033
00:27:25,180 --> 00:27:28,400
we have again at the corners and then we
have in the center of the faces now

1034
00:27:28,400 --> 00:27:28,410
have in the center of the faces now

1035
00:27:28,410 --> 00:27:36,890
have in the center of the faces now
let's think about how many metal atoms

1036
00:27:36,890 --> 00:27:36,900
let's think about how many metal atoms

1037
00:27:36,900 --> 00:27:41,610
let's think about how many metal atoms
actually belongs to one unit cell in a

1038
00:27:41,610 --> 00:27:41,620
actually belongs to one unit cell in a

1039
00:27:41,620 --> 00:27:46,260
actually belongs to one unit cell in a
metal lattice right metal lattice we can

1040
00:27:46,260 --> 00:27:46,270
metal lattice right metal lattice we can

1041
00:27:46,270 --> 00:27:51,170
metal lattice right metal lattice we can
easily find it out here for example in

1042
00:27:51,170 --> 00:27:51,180

1043
00:27:51,180 --> 00:27:56,130
simple cubic lattice actually this is

1044
00:27:56,130 --> 00:27:56,140
simple cubic lattice actually this is

1045
00:27:56,140 --> 00:27:59,340
simple cubic lattice actually this is
going to be the unit cell exactly right

1046
00:27:59,340 --> 00:27:59,350
going to be the unit cell exactly right

1047
00:27:59,350 --> 00:28:02,310
going to be the unit cell exactly right
now remember in the previous one here

1048
00:28:02,310 --> 00:28:02,320
now remember in the previous one here

1049
00:28:02,320 --> 00:28:04,770
now remember in the previous one here
let's look at there now this is this is

1050
00:28:04,770 --> 00:28:04,780
let's look at there now this is this is

1051
00:28:04,780 --> 00:28:06,820
let's look at there now this is this is
the same as this but

1052
00:28:06,820 --> 00:28:06,830
the same as this but

1053
00:28:06,830 --> 00:28:09,310
the same as this but
these sphere if you consider one sphere

1054
00:28:09,310 --> 00:28:09,320
these sphere if you consider one sphere

1055
00:28:09,320 --> 00:28:13,630
these sphere if you consider one sphere
or metal atom only 1/8 of this metal

1056
00:28:13,630 --> 00:28:13,640
or metal atom only 1/8 of this metal

1057
00:28:13,640 --> 00:28:17,200
or metal atom only 1/8 of this metal
atom or this sphere is inside of this

1058
00:28:17,200 --> 00:28:17,210
atom or this sphere is inside of this

1059
00:28:17,210 --> 00:28:20,800
atom or this sphere is inside of this
cube now how about the others the others

1060
00:28:20,800 --> 00:28:20,810
cube now how about the others the others

1061
00:28:20,810 --> 00:28:23,770
cube now how about the others the others
belongs to the other unit cells the

1062
00:28:23,770 --> 00:28:23,780
belongs to the other unit cells the

1063
00:28:23,780 --> 00:28:26,770
belongs to the other unit cells the
other cube actually one corner here is

1064
00:28:26,770 --> 00:28:26,780
other cube actually one corner here is

1065
00:28:26,780 --> 00:28:29,080
other cube actually one corner here is
shared in the lattice three-dimensional

1066
00:28:29,080 --> 00:28:29,090
shared in the lattice three-dimensional

1067
00:28:29,090 --> 00:28:32,770
shared in the lattice three-dimensional
lattice is shared by 8 cubes and that

1068
00:28:32,770 --> 00:28:32,780
lattice is shared by 8 cubes and that

1069
00:28:32,780 --> 00:28:35,590
lattice is shared by 8 cubes and that
means that any atom on the corner of the

1070
00:28:35,590 --> 00:28:35,600
means that any atom on the corner of the

1071
00:28:35,600 --> 00:28:39,220
means that any atom on the corner of the
cube in a simple cubic unit cell only

1072
00:28:39,220 --> 00:28:39,230
cube in a simple cubic unit cell only

1073
00:28:39,230 --> 00:28:43,240
cube in a simple cubic unit cell only
1/8 belongs to that unit cell and 7/8

1074
00:28:43,240 --> 00:28:43,250
1/8 belongs to that unit cell and 7/8

1075
00:28:43,250 --> 00:28:45,010
1/8 belongs to that unit cell and 7/8
belongs to the others clear

1076
00:28:45,010 --> 00:28:45,020
belongs to the others clear

1077
00:28:45,020 --> 00:28:48,280
belongs to the others clear
now if considering that now for example

1078
00:28:48,280 --> 00:28:48,290
now if considering that now for example

1079
00:28:48,290 --> 00:28:52,360
now if considering that now for example
if you consider the atom metal atom

1080
00:28:52,360 --> 00:28:52,370
if you consider the atom metal atom

1081
00:28:52,370 --> 00:28:56,140
if you consider the atom metal atom
which in the center of this cube that

1082
00:28:56,140 --> 00:28:56,150
which in the center of this cube that

1083
00:28:56,150 --> 00:28:58,540
which in the center of this cube that
belongs all of them belongs to this unit

1084
00:28:58,540 --> 00:28:58,550
belongs all of them belongs to this unit

1085
00:28:58,550 --> 00:29:03,070
belongs all of them belongs to this unit
cell right now but any atom which is in

1086
00:29:03,070 --> 00:29:03,080
cell right now but any atom which is in

1087
00:29:03,080 --> 00:29:06,400
cell right now but any atom which is in
the center of the faces half belongs to

1088
00:29:06,400 --> 00:29:06,410
the center of the faces half belongs to

1089
00:29:06,410 --> 00:29:08,290
the center of the faces half belongs to
one unit cell half belongs to the other

1090
00:29:08,290 --> 00:29:08,300
one unit cell half belongs to the other

1091
00:29:08,300 --> 00:29:11,440
one unit cell half belongs to the other
unit cell so considering these we can

1092
00:29:11,440 --> 00:29:11,450
unit cell so considering these we can

1093
00:29:11,450 --> 00:29:16,140
unit cell so considering these we can
simply calculate how many metal atoms

1094
00:29:16,140 --> 00:29:16,150
simply calculate how many metal atoms

1095
00:29:16,150 --> 00:29:21,040
simply calculate how many metal atoms
will make a unit cell in the letters in

1096
00:29:21,040 --> 00:29:21,050
will make a unit cell in the letters in

1097
00:29:21,050 --> 00:29:23,410
will make a unit cell in the letters in
three different lattice structures

1098
00:29:23,410 --> 00:29:23,420
three different lattice structures

1099
00:29:23,420 --> 00:29:26,200
three different lattice structures
simple cubic face a body centered and

1100
00:29:26,200 --> 00:29:26,210
simple cubic face a body centered and

1101
00:29:26,210 --> 00:29:29,200
simple cubic face a body centered and
face Center if you take the simple cubic

1102
00:29:29,200 --> 00:29:29,210
face Center if you take the simple cubic

1103
00:29:29,210 --> 00:29:32,710
face Center if you take the simple cubic
in this case every corner is shared by 8

1104
00:29:32,710 --> 00:29:32,720
in this case every corner is shared by 8

1105
00:29:32,720 --> 00:29:35,500
in this case every corner is shared by 8
unit cells that means 1 over 8 belongs

1106
00:29:35,500 --> 00:29:35,510
unit cells that means 1 over 8 belongs

1107
00:29:35,510 --> 00:29:38,410
unit cells that means 1 over 8 belongs
to this since we have eight corners one

1108
00:29:38,410 --> 00:29:38,420
to this since we have eight corners one

1109
00:29:38,420 --> 00:29:41,760
to this since we have eight corners one
over eight times eight one metal atom

1110
00:29:41,760 --> 00:29:41,770
over eight times eight one metal atom

1111
00:29:41,770 --> 00:29:46,660
over eight times eight one metal atom
makes a unit cell in a simple cubic unit

1112
00:29:46,660 --> 00:29:46,670
makes a unit cell in a simple cubic unit

1113
00:29:46,670 --> 00:29:50,830
makes a unit cell in a simple cubic unit
cell lattice right in a simple cubic

1114
00:29:50,830 --> 00:29:50,840
cell lattice right in a simple cubic

1115
00:29:50,840 --> 00:29:53,350
cell lattice right in a simple cubic
lattice I should say probably that's a

1116
00:29:53,350 --> 00:29:53,360
lattice I should say probably that's a

1117
00:29:53,360 --> 00:29:56,020
lattice I should say probably that's a
unit cell now if you come over here

1118
00:29:56,020 --> 00:29:56,030
unit cell now if you come over here

1119
00:29:56,030 --> 00:29:58,630
unit cell now if you come over here
again eight of those from the corner one

1120
00:29:58,630 --> 00:29:58,640
again eight of those from the corner one

1121
00:29:58,640 --> 00:30:00,580
again eight of those from the corner one
over eight times eight and that means

1122
00:30:00,580 --> 00:30:00,590
over eight times eight and that means

1123
00:30:00,590 --> 00:30:03,580
over eight times eight and that means
one coming from the corner and one

1124
00:30:03,580 --> 00:30:03,590
one coming from the corner and one

1125
00:30:03,590 --> 00:30:06,850
one coming from the corner and one
inside over here that makes two atoms

1126
00:30:06,850 --> 00:30:06,860
inside over here that makes two atoms

1127
00:30:06,860 --> 00:30:11,220
inside over here that makes two atoms
will make a unit cell in a body centered

1128
00:30:11,220 --> 00:30:11,230
will make a unit cell in a body centered

1129
00:30:11,230 --> 00:30:14,770
will make a unit cell in a body centered
lattice cubic lattice right in three

1130
00:30:14,770 --> 00:30:14,780
lattice cubic lattice right in three

1131
00:30:14,780 --> 00:30:16,360
lattice cubic lattice right in three
dimensions now if you take the face

1132
00:30:16,360 --> 00:30:16,370
dimensions now if you take the face

1133
00:30:16,370 --> 00:30:18,850
dimensions now if you take the face
center in this case one from the corners

1134
00:30:18,850 --> 00:30:18,860
center in this case one from the corners

1135
00:30:18,860 --> 00:30:20,460
center in this case one from the corners
again one over eight times eight

1136
00:30:20,460 --> 00:30:20,470
again one over eight times eight

1137
00:30:20,470 --> 00:30:23,370
again one over eight times eight
but there are six phases and each phase

1138
00:30:23,370 --> 00:30:23,380
but there are six phases and each phase

1139
00:30:23,380 --> 00:30:26,040
but there are six phases and each phase
has one in the center half belongs to

1140
00:30:26,040 --> 00:30:26,050
has one in the center half belongs to

1141
00:30:26,050 --> 00:30:28,290
has one in the center half belongs to
this half belongs to the other six times

1142
00:30:28,290 --> 00:30:28,300
this half belongs to the other six times

1143
00:30:28,300 --> 00:30:30,720
this half belongs to the other six times
one over two three coming from the

1144
00:30:30,720 --> 00:30:30,730
one over two three coming from the

1145
00:30:30,730 --> 00:30:34,680
one over two three coming from the
phases that means four actually metal

1146
00:30:34,680 --> 00:30:34,690
phases that means four actually metal

1147
00:30:34,690 --> 00:30:39,090
phases that means four actually metal
atoms will make a unit cell in phase

1148
00:30:39,090 --> 00:30:39,100
atoms will make a unit cell in phase

1149
00:30:39,100 --> 00:30:43,170
atoms will make a unit cell in phase
centered lattice in phase centered

1150
00:30:43,170 --> 00:30:43,180
centered lattice in phase centered

1151
00:30:43,180 --> 00:30:44,760
centered lattice in phase centered
lattice and these are actually when we

1152
00:30:44,760 --> 00:30:44,770
lattice and these are actually when we

1153
00:30:44,770 --> 00:30:46,290
lattice and these are actually when we
say unit cell actually these are the

1154
00:30:46,290 --> 00:30:46,300
say unit cell actually these are the

1155
00:30:46,300 --> 00:30:48,900
say unit cell actually these are the
unit cells right and when you take those

1156
00:30:48,900 --> 00:30:48,910
unit cells right and when you take those

1157
00:30:48,910 --> 00:30:51,300
unit cells right and when you take those
unit cells put them together you get the

1158
00:30:51,300 --> 00:30:51,310
unit cells put them together you get the

1159
00:30:51,310 --> 00:30:59,180
unit cells put them together you get the
lattice now let's see before we go here

1160
00:30:59,180 --> 00:30:59,190
lattice now let's see before we go here

1161
00:30:59,190 --> 00:31:00,720
lattice now let's see before we go here
okay

1162
00:31:00,720 --> 00:31:00,730
okay

1163
00:31:00,730 --> 00:31:08,630
okay
this is a closed packing structure now

1164
00:31:08,630 --> 00:31:08,640

1165
00:31:08,640 --> 00:31:18,920
in nature when a solid forms it try to

1166
00:31:18,920 --> 00:31:18,930
in nature when a solid forms it try to

1167
00:31:18,930 --> 00:31:22,350
in nature when a solid forms it try to
pack the atoms or the molecules or

1168
00:31:22,350 --> 00:31:22,360
pack the atoms or the molecules or

1169
00:31:22,360 --> 00:31:26,610
pack the atoms or the molecules or
whatever as close as possible to get the

1170
00:31:26,610 --> 00:31:26,620
whatever as close as possible to get the

1171
00:31:26,620 --> 00:31:30,510
whatever as close as possible to get the
highest density and occupy the smallest

1172
00:31:30,510 --> 00:31:30,520
highest density and occupy the smallest

1173
00:31:30,520 --> 00:31:34,650
highest density and occupy the smallest
volume right and now the question here

1174
00:31:34,650 --> 00:31:34,660
volume right and now the question here

1175
00:31:34,660 --> 00:31:42,180
volume right and now the question here
is if I simply have spares the same size

1176
00:31:42,180 --> 00:31:42,190
is if I simply have spares the same size

1177
00:31:42,190 --> 00:31:46,730
is if I simply have spares the same size
spheres and if I would like to pack them

1178
00:31:46,730 --> 00:31:46,740
spheres and if I would like to pack them

1179
00:31:46,740 --> 00:31:49,710
spheres and if I would like to pack them
closest possible way closer to each

1180
00:31:49,710 --> 00:31:49,720
closest possible way closer to each

1181
00:31:49,720 --> 00:31:52,770
closest possible way closer to each
other possible what will be the

1182
00:31:52,770 --> 00:31:52,780
other possible what will be the

1183
00:31:52,780 --> 00:31:57,380
other possible what will be the
structure and actually the structure

1184
00:31:57,380 --> 00:31:57,390
structure and actually the structure

1185
00:31:57,390 --> 00:32:04,280
structure and actually the structure
will be phase centered lattice or

1186
00:32:04,280 --> 00:32:04,290
will be phase centered lattice or

1187
00:32:04,290 --> 00:32:09,530
will be phase centered lattice or
hexagonal lattice there's only two types

1188
00:32:09,530 --> 00:32:09,540
hexagonal lattice there's only two types

1189
00:32:09,540 --> 00:32:13,850
hexagonal lattice there's only two types
now how can we achieve closest packed

1190
00:32:13,850 --> 00:32:13,860
now how can we achieve closest packed

1191
00:32:13,860 --> 00:32:16,560
now how can we achieve closest packed
structure close the pack structure with

1192
00:32:16,560 --> 00:32:16,570
structure close the pack structure with

1193
00:32:16,570 --> 00:32:21,900
structure close the pack structure with
again take in same size fares that means

1194
00:32:21,900 --> 00:32:21,910
again take in same size fares that means

1195
00:32:21,910 --> 00:32:25,440
again take in same size fares that means
that we will try to put maximum number

1196
00:32:25,440 --> 00:32:25,450
that we will try to put maximum number

1197
00:32:25,450 --> 00:32:29,820
that we will try to put maximum number
of spheres in a given volume in a given

1198
00:32:29,820 --> 00:32:29,830
of spheres in a given volume in a given

1199
00:32:29,830 --> 00:32:33,270
of spheres in a given volume in a given
volume how can we pack them to get the

1200
00:32:33,270 --> 00:32:33,280
volume how can we pack them to get the

1201
00:32:33,280 --> 00:32:33,600
volume how can we pack them to get the
met

1202
00:32:33,600 --> 00:32:33,610
met

1203
00:32:33,610 --> 00:32:35,760
met
umhum number of spheres in that given

1204
00:32:35,760 --> 00:32:35,770
umhum number of spheres in that given

1205
00:32:35,770 --> 00:32:38,730
umhum number of spheres in that given
volume the first layer would be like

1206
00:32:38,730 --> 00:32:38,740
volume the first layer would be like

1207
00:32:38,740 --> 00:32:40,560
volume the first layer would be like
this night you will just take the same

1208
00:32:40,560 --> 00:32:40,570
this night you will just take the same

1209
00:32:40,570 --> 00:32:42,840
this night you will just take the same
size fares and they're all touching each

1210
00:32:42,840 --> 00:32:42,850
size fares and they're all touching each

1211
00:32:42,850 --> 00:32:50,430
size fares and they're all touching each
other this is one roll okay and then the

1212
00:32:50,430 --> 00:32:50,440
other this is one roll okay and then the

1213
00:32:50,440 --> 00:32:52,500
other this is one roll okay and then the
second row would be we have to put it

1214
00:32:52,500 --> 00:32:52,510
second row would be we have to put it

1215
00:32:52,510 --> 00:32:54,810
second row would be we have to put it
here if I'm going to put that closest

1216
00:32:54,810 --> 00:32:54,820
here if I'm going to put that closest

1217
00:32:54,820 --> 00:33:01,200
here if I'm going to put that closest
like this and they're all touching each

1218
00:33:01,200 --> 00:33:01,210
like this and they're all touching each

1219
00:33:01,210 --> 00:33:08,539
like this and they're all touching each
other's now the third would go here I

1220
00:33:08,539 --> 00:33:08,549

1221
00:33:08,549 --> 00:33:13,230
know this is one layer right now when

1222
00:33:13,230 --> 00:33:13,240
know this is one layer right now when

1223
00:33:13,240 --> 00:33:15,750
know this is one layer right now when
you simply put the second layer on the

1224
00:33:15,750 --> 00:33:15,760
you simply put the second layer on the

1225
00:33:15,760 --> 00:33:18,830
you simply put the second layer on the
top same size fears you will simply take

1226
00:33:18,830 --> 00:33:18,840
top same size fears you will simply take

1227
00:33:18,840 --> 00:33:21,930
top same size fears you will simply take
you have to put them in a depression of

1228
00:33:21,930 --> 00:33:21,940
you have to put them in a depression of

1229
00:33:21,940 --> 00:33:24,900
you have to put them in a depression of
three spares in this layer that would be

1230
00:33:24,900 --> 00:33:24,910
three spares in this layer that would be

1231
00:33:24,910 --> 00:33:28,440
three spares in this layer that would be
over here on the top of here or maybe

1232
00:33:28,440 --> 00:33:28,450
over here on the top of here or maybe

1233
00:33:28,450 --> 00:33:30,750
over here on the top of here or maybe
here if you put there you can't put it

1234
00:33:30,750 --> 00:33:30,760
here if you put there you can't put it

1235
00:33:30,760 --> 00:33:36,450
here if you put there you can't put it
there right and then here here and here

1236
00:33:36,450 --> 00:33:36,460
there right and then here here and here

1237
00:33:36,460 --> 00:33:40,200
there right and then here here and here
actually you have one here like this and

1238
00:33:40,200 --> 00:33:40,210
actually you have one here like this and

1239
00:33:40,210 --> 00:33:41,820
actually you have one here like this and
the other one like that if you put it

1240
00:33:41,820 --> 00:33:41,830
the other one like that if you put it

1241
00:33:41,830 --> 00:33:44,400
the other one like that if you put it
there and this is going to be the second

1242
00:33:44,400 --> 00:33:44,410
there and this is going to be the second

1243
00:33:44,410 --> 00:33:47,580
there and this is going to be the second
layer you see again and then we'll have

1244
00:33:47,580 --> 00:33:47,590
layer you see again and then we'll have

1245
00:33:47,590 --> 00:33:51,960
layer you see again and then we'll have
the other layer over here so you have

1246
00:33:51,960 --> 00:33:51,970
the other layer over here so you have

1247
00:33:51,970 --> 00:33:54,270
the other layer over here so you have
one layer of spheres closest put

1248
00:33:54,270 --> 00:33:54,280
one layer of spheres closest put

1249
00:33:54,280 --> 00:33:56,610
one layer of spheres closest put
together and then the second layer is

1250
00:33:56,610 --> 00:33:56,620
together and then the second layer is

1251
00:33:56,620 --> 00:33:58,590
together and then the second layer is
put on the top of that but you have to

1252
00:33:58,590 --> 00:33:58,600
put on the top of that but you have to

1253
00:33:58,600 --> 00:34:00,419
put on the top of that but you have to
use the depressions here

1254
00:34:00,419 --> 00:34:00,429
use the depressions here

1255
00:34:00,429 --> 00:34:04,470
use the depressions here
to get the maximum filling or packing I

1256
00:34:04,470 --> 00:34:04,480
to get the maximum filling or packing I

1257
00:34:04,480 --> 00:34:06,299
to get the maximum filling or packing I
should say and that means they are a

1258
00:34:06,299 --> 00:34:06,309
should say and that means they are a

1259
00:34:06,309 --> 00:34:10,470
should say and that means they are a
little bit moved one side from this now

1260
00:34:10,470 --> 00:34:10,480
little bit moved one side from this now

1261
00:34:10,480 --> 00:34:13,590
little bit moved one side from this now
when you put the third layer on there

1262
00:34:13,590 --> 00:34:13,600
when you put the third layer on there

1263
00:34:13,600 --> 00:34:16,710
when you put the third layer on there
are two possibilities you can either put

1264
00:34:16,710 --> 00:34:16,720
are two possibilities you can either put

1265
00:34:16,720 --> 00:34:21,149
are two possibilities you can either put
those on the top of these here for

1266
00:34:21,149 --> 00:34:21,159
those on the top of these here for

1267
00:34:21,159 --> 00:34:25,200
those on the top of these here for
example or you can just put it a little

1268
00:34:25,200 --> 00:34:25,210
example or you can just put it a little

1269
00:34:25,210 --> 00:34:29,460
example or you can just put it a little
bit shifted again so the structures

1270
00:34:29,460 --> 00:34:29,470
bit shifted again so the structures

1271
00:34:29,470 --> 00:34:37,680
bit shifted again so the structures
there is called a P a B a B type what

1272
00:34:37,680 --> 00:34:37,690
there is called a P a B a B type what

1273
00:34:37,690 --> 00:34:40,080
there is called a P a B a B type what
does that means you put one layer second

1274
00:34:40,080 --> 00:34:40,090
does that means you put one layer second

1275
00:34:40,090 --> 00:34:42,389
does that means you put one layer second
layer is little off has to be off now

1276
00:34:42,389 --> 00:34:42,399
layer is little off has to be off now

1277
00:34:42,399 --> 00:34:43,919
layer is little off has to be off now
the third layer will be on the top off

1278
00:34:43,919 --> 00:34:43,929
the third layer will be on the top off

1279
00:34:43,929 --> 00:34:46,730
the third layer will be on the top off
the first so it goes like Abe

1280
00:34:46,730 --> 00:34:46,740
the first so it goes like Abe

1281
00:34:46,740 --> 00:34:49,730
the first so it goes like Abe
a B a B type No first layer second layer

1282
00:34:49,730 --> 00:34:49,740
a B a B type No first layer second layer

1283
00:34:49,740 --> 00:34:52,930
a B a B type No first layer second layer
third layer and so on or if you put it

1284
00:34:52,930 --> 00:34:52,940
third layer and so on or if you put it

1285
00:34:52,940 --> 00:34:55,520
third layer and so on or if you put it
that if you put the third layer not on

1286
00:34:55,520 --> 00:34:55,530
that if you put the third layer not on

1287
00:34:55,530 --> 00:34:57,800
that if you put the third layer not on
the top of the first layer it will be

1288
00:34:57,800 --> 00:34:57,810
the top of the first layer it will be

1289
00:34:57,810 --> 00:34:59,600
the top of the first layer it will be
shifted a little bit one way and that's

1290
00:34:59,600 --> 00:34:59,610
shifted a little bit one way and that's

1291
00:34:59,610 --> 00:35:10,160
shifted a little bit one way and that's
called ABC ABC ABC type now both of

1292
00:35:10,160 --> 00:35:10,170
called ABC ABC ABC type now both of

1293
00:35:10,170 --> 00:35:16,310
called ABC ABC ABC type now both of
these pakkun are closest packing that

1294
00:35:16,310 --> 00:35:16,320
these pakkun are closest packing that

1295
00:35:16,320 --> 00:35:18,290
these pakkun are closest packing that
means by using these two types of

1296
00:35:18,290 --> 00:35:18,300
means by using these two types of

1297
00:35:18,300 --> 00:35:21,700
means by using these two types of
packing you can put the same number of

1298
00:35:21,700 --> 00:35:21,710
packing you can put the same number of

1299
00:35:21,710 --> 00:35:24,620
packing you can put the same number of
spheres in a given volume that means

1300
00:35:24,620 --> 00:35:24,630
spheres in a given volume that means

1301
00:35:24,630 --> 00:35:26,060
spheres in a given volume that means
there's no difference what is the

1302
00:35:26,060 --> 00:35:26,070
there's no difference what is the

1303
00:35:26,070 --> 00:35:27,590
there's no difference what is the
difference the difference is the unit

1304
00:35:27,590 --> 00:35:27,600
difference the difference is the unit

1305
00:35:27,600 --> 00:35:30,410
difference the difference is the unit
cells unit cells are different in this

1306
00:35:30,410 --> 00:35:30,420
cells unit cells are different in this

1307
00:35:30,420 --> 00:35:33,500
cells unit cells are different in this
case the unit cells is hexagonal unit

1308
00:35:33,500 --> 00:35:33,510
case the unit cells is hexagonal unit

1309
00:35:33,510 --> 00:35:42,500
case the unit cells is hexagonal unit
cell exactly no unit cell in this case

1310
00:35:42,500 --> 00:35:42,510
cell exactly no unit cell in this case

1311
00:35:42,510 --> 00:35:45,350
cell exactly no unit cell in this case
it is face centered cubic unit cells

1312
00:35:45,350 --> 00:35:45,360
it is face centered cubic unit cells

1313
00:35:45,360 --> 00:35:52,160
it is face centered cubic unit cells
face centered cubic now this structure

1314
00:35:52,160 --> 00:35:52,170
face centered cubic now this structure

1315
00:35:52,170 --> 00:35:57,520
face centered cubic now this structure
is called hexagonal close pack an HCP

1316
00:35:57,520 --> 00:35:57,530
is called hexagonal close pack an HCP

1317
00:35:57,530 --> 00:35:59,870
is called hexagonal close pack an HCP
hexagonal close packing and this

1318
00:35:59,870 --> 00:35:59,880
hexagonal close packing and this

1319
00:35:59,880 --> 00:36:02,900
hexagonal close packing and this
structure is called cubic close pack and

1320
00:36:02,900 --> 00:36:02,910
structure is called cubic close pack and

1321
00:36:02,910 --> 00:36:06,140
structure is called cubic close pack and
CCP now the difference the only

1322
00:36:06,140 --> 00:36:06,150
CCP now the difference the only

1323
00:36:06,150 --> 00:36:12,520
CCP now the difference the only
difference is the unit cells in terms of

1324
00:36:12,520 --> 00:36:12,530
difference is the unit cells in terms of

1325
00:36:12,530 --> 00:36:15,500
difference is the unit cells in terms of
highest packing efficiency both are the

1326
00:36:15,500 --> 00:36:15,510
highest packing efficiency both are the

1327
00:36:15,510 --> 00:36:18,109
highest packing efficiency both are the
same both are the same same effect what

1328
00:36:18,109 --> 00:36:18,119
same both are the same same effect what

1329
00:36:18,119 --> 00:36:20,270
same both are the same same effect what
does that means that means that I will

1330
00:36:20,270 --> 00:36:20,280
does that means that means that I will

1331
00:36:20,280 --> 00:36:24,020
does that means that means that I will
put the same number of sphere same size

1332
00:36:24,020 --> 00:36:24,030
put the same number of sphere same size

1333
00:36:24,030 --> 00:36:28,400
put the same number of sphere same size
spheres in a given volume by using these

1334
00:36:28,400 --> 00:36:28,410
spheres in a given volume by using these

1335
00:36:28,410 --> 00:36:33,349
spheres in a given volume by using these
two types of packing off the spheres now

1336
00:36:33,349 --> 00:36:33,359
two types of packing off the spheres now

1337
00:36:33,359 --> 00:36:37,099
two types of packing off the spheres now
let's see if I can show you here for

1338
00:36:37,099 --> 00:36:37,109
let's see if I can show you here for

1339
00:36:37,109 --> 00:36:41,210
let's see if I can show you here for
example now this one you see you have a

1340
00:36:41,210 --> 00:36:41,220
example now this one you see you have a

1341
00:36:41,220 --> 00:36:44,330
example now this one you see you have a
layer of spheres one layer the second

1342
00:36:44,330 --> 00:36:44,340
layer of spheres one layer the second

1343
00:36:44,340 --> 00:36:46,430
layer of spheres one layer the second
layer put sort of little bit shifted on

1344
00:36:46,430 --> 00:36:46,440
layer put sort of little bit shifted on

1345
00:36:46,440 --> 00:36:48,290
layer put sort of little bit shifted on
the depressions now the third layer

1346
00:36:48,290 --> 00:36:48,300
the depressions now the third layer

1347
00:36:48,300 --> 00:36:51,320
the depressions now the third layer
right on the top of that and now the

1348
00:36:51,320 --> 00:36:51,330
right on the top of that and now the

1349
00:36:51,330 --> 00:36:53,270
right on the top of that and now the
fourth layer is on the top of the second

1350
00:36:53,270 --> 00:36:53,280
fourth layer is on the top of the second

1351
00:36:53,280 --> 00:36:55,640
fourth layer is on the top of the second
layer like this this is the a.b a.b a.b

1352
00:36:55,640 --> 00:36:55,650
layer like this this is the a.b a.b a.b

1353
00:36:55,650 --> 00:36:58,400
layer like this this is the a.b a.b a.b
type structure closest pack structure

1354
00:36:58,400 --> 00:36:58,410
type structure closest pack structure

1355
00:36:58,410 --> 00:37:00,290
type structure closest pack structure
and it's called HC

1356
00:37:00,290 --> 00:37:00,300
and it's called HC

1357
00:37:00,300 --> 00:37:02,660
and it's called HC
he hexagonal closed back in because the

1358
00:37:02,660 --> 00:37:02,670
he hexagonal closed back in because the

1359
00:37:02,670 --> 00:37:06,050
he hexagonal closed back in because the
unit cell is exact hexagon hexagonal

1360
00:37:06,050 --> 00:37:06,060
unit cell is exact hexagon hexagonal

1361
00:37:06,060 --> 00:37:08,450
unit cell is exact hexagon hexagonal
unit cell I should say this one is like

1362
00:37:08,450 --> 00:37:08,460
unit cell I should say this one is like

1363
00:37:08,460 --> 00:37:11,120
unit cell I should say this one is like
you have first layer second layer is a

1364
00:37:11,120 --> 00:37:11,130
you have first layer second layer is a

1365
00:37:11,130 --> 00:37:13,220
you have first layer second layer is a
little bit sort of shifted put in a

1366
00:37:13,220 --> 00:37:13,230
little bit sort of shifted put in a

1367
00:37:13,230 --> 00:37:14,930
little bit sort of shifted put in a
depression the third is also a little

1368
00:37:14,930 --> 00:37:14,940
depression the third is also a little

1369
00:37:14,940 --> 00:37:17,720
depression the third is also a little
shifted and then the fourth one is on

1370
00:37:17,720 --> 00:37:17,730
shifted and then the fourth one is on

1371
00:37:17,730 --> 00:37:20,710
shifted and then the fourth one is on
the top of the first so this goes again

1372
00:37:20,710 --> 00:37:20,720
the top of the first so this goes again

1373
00:37:20,720 --> 00:37:25,310
the top of the first so this goes again
ABC ABC ABC and the unit cell is the

1374
00:37:25,310 --> 00:37:25,320
ABC ABC ABC and the unit cell is the

1375
00:37:25,320 --> 00:37:28,040
ABC ABC ABC and the unit cell is the
phase centered unit cell and the other

1376
00:37:28,040 --> 00:37:28,050
phase centered unit cell and the other

1377
00:37:28,050 --> 00:37:29,720
phase centered unit cell and the other
one this is the hexagonal unit cell

1378
00:37:29,720 --> 00:37:29,730
one this is the hexagonal unit cell

1379
00:37:29,730 --> 00:37:31,520
one this is the hexagonal unit cell
remember this is just the one part of

1380
00:37:31,520 --> 00:37:31,530
remember this is just the one part of

1381
00:37:31,530 --> 00:37:35,870
remember this is just the one part of
that it is mainly it's simply simply the

1382
00:37:35,870 --> 00:37:35,880
that it is mainly it's simply simply the

1383
00:37:35,880 --> 00:37:38,360
that it is mainly it's simply simply the
one third of this or you can consider

1384
00:37:38,360 --> 00:37:38,370
one third of this or you can consider

1385
00:37:38,370 --> 00:37:40,880
one third of this or you can consider
the whole things as the unit cell as a

1386
00:37:40,880 --> 00:37:40,890
the whole things as the unit cell as a

1387
00:37:40,890 --> 00:37:44,920
the whole things as the unit cell as a
matter of fact so these are the two

1388
00:37:44,920 --> 00:37:44,930
matter of fact so these are the two

1389
00:37:44,930 --> 00:37:49,100
matter of fact so these are the two
closest packed structures now let's do a

1390
00:37:49,100 --> 00:37:49,110
closest packed structures now let's do a

1391
00:37:49,110 --> 00:37:54,370
closest packed structures now let's do a
calculation and see if we can find out

1392
00:37:54,370 --> 00:37:54,380
calculation and see if we can find out

1393
00:37:54,380 --> 00:38:01,820
calculation and see if we can find out
what is the packing efficiency in these

1394
00:38:01,820 --> 00:38:01,830
what is the packing efficiency in these

1395
00:38:01,830 --> 00:38:29,940
what is the packing efficiency in these
cases in close packing structures

1396
00:38:29,940 --> 00:38:29,950

1397
00:38:29,950 --> 00:38:32,290
now what does that means that simply

1398
00:38:32,290 --> 00:38:32,300
now what does that means that simply

1399
00:38:32,300 --> 00:38:37,810
now what does that means that simply
means we will try to find out what

1400
00:38:37,810 --> 00:38:37,820
means we will try to find out what

1401
00:38:37,820 --> 00:38:43,960
means we will try to find out what
fraction of space is filled with the

1402
00:38:43,960 --> 00:38:43,970
fraction of space is filled with the

1403
00:38:43,970 --> 00:38:49,240
fraction of space is filled with the
atoms and what fraction is empty the

1404
00:38:49,240 --> 00:38:49,250
atoms and what fraction is empty the

1405
00:38:49,250 --> 00:38:53,020
atoms and what fraction is empty the
whole space right now first let's take

1406
00:38:53,020 --> 00:38:53,030
whole space right now first let's take

1407
00:38:53,030 --> 00:39:03,760
whole space right now first let's take
the simple cubic case cubic lattice now

1408
00:39:03,760 --> 00:39:03,770
the simple cubic case cubic lattice now

1409
00:39:03,770 --> 00:39:10,060
the simple cubic case cubic lattice now
the unit cell remember is cube like this

1410
00:39:10,060 --> 00:39:10,070
the unit cell remember is cube like this

1411
00:39:10,070 --> 00:39:15,790
the unit cell remember is cube like this
and we have the metal atoms like

1412
00:39:15,790 --> 00:39:15,800
and we have the metal atoms like

1413
00:39:15,800 --> 00:39:21,930
and we have the metal atoms like
spherical on the top here like this

1414
00:39:21,930 --> 00:39:21,940

1415
00:39:21,940 --> 00:39:24,640
they're all touching each other so if I

1416
00:39:24,640 --> 00:39:24,650
they're all touching each other so if I

1417
00:39:24,650 --> 00:39:28,240
they're all touching each other so if I
consider the edge of this unit cell that

1418
00:39:28,240 --> 00:39:28,250
consider the edge of this unit cell that

1419
00:39:28,250 --> 00:39:29,380
consider the edge of this unit cell that
will be equal to what

1420
00:39:29,380 --> 00:39:29,390
will be equal to what

1421
00:39:29,390 --> 00:39:39,099
will be equal to what
edge a is edge of the unit cell actually

1422
00:39:39,099 --> 00:39:39,109
edge a is edge of the unit cell actually

1423
00:39:39,109 --> 00:39:42,790
edge a is edge of the unit cell actually
this is a cube right will be equal to

1424
00:39:42,790 --> 00:39:42,800
this is a cube right will be equal to

1425
00:39:42,800 --> 00:39:50,200
this is a cube right will be equal to
what equals to this is our this is our

1426
00:39:50,200 --> 00:39:50,210
what equals to this is our this is our

1427
00:39:50,210 --> 00:39:54,370
what equals to this is our this is our
to our right it's simply to our to our

1428
00:39:54,370 --> 00:39:54,380
to our right it's simply to our to our

1429
00:39:54,380 --> 00:39:59,590
to our right it's simply to our to our
like this okay now let's remember how

1430
00:39:59,590 --> 00:39:59,600
like this okay now let's remember how

1431
00:39:59,600 --> 00:40:06,340
like this okay now let's remember how
many atoms or spheres will make a unit

1432
00:40:06,340 --> 00:40:06,350
many atoms or spheres will make a unit

1433
00:40:06,350 --> 00:40:08,740
many atoms or spheres will make a unit
cell simple cubic unit cell or how many

1434
00:40:08,740 --> 00:40:08,750
cell simple cubic unit cell or how many

1435
00:40:08,750 --> 00:40:11,470
cell simple cubic unit cell or how many
atoms belongs to one unit cell in the

1436
00:40:11,470 --> 00:40:11,480
atoms belongs to one unit cell in the

1437
00:40:11,480 --> 00:40:12,960
atoms belongs to one unit cell in the
lattice in two dimensional structures

1438
00:40:12,960 --> 00:40:12,970
lattice in two dimensional structures

1439
00:40:12,970 --> 00:40:16,510
lattice in two dimensional structures
one right because remember only one

1440
00:40:16,510 --> 00:40:16,520
one right because remember only one

1441
00:40:16,520 --> 00:40:18,760
one right because remember only one
eight of these are inside of this cube

1442
00:40:18,760 --> 00:40:18,770
eight of these are inside of this cube

1443
00:40:18,770 --> 00:40:22,330
eight of these are inside of this cube
so one and what is the volume so the

1444
00:40:22,330 --> 00:40:22,340
so one and what is the volume so the

1445
00:40:22,340 --> 00:40:29,290
so one and what is the volume so the
volume occupied here will be equal to

1446
00:40:29,290 --> 00:40:29,300
volume occupied here will be equal to

1447
00:40:29,300 --> 00:40:32,830
volume occupied here will be equal to
the volume of one sphere right and the

1448
00:40:32,830 --> 00:40:32,840
the volume of one sphere right and the

1449
00:40:32,840 --> 00:40:35,559
the volume of one sphere right and the
volume of one sphere is four all

1450
00:40:35,559 --> 00:40:35,569
volume of one sphere is four all

1451
00:40:35,569 --> 00:40:39,789
volume of one sphere is four all
three PI R to the Q this is it

1452
00:40:39,789 --> 00:40:39,799
three PI R to the Q this is it

1453
00:40:39,799 --> 00:40:45,130
three PI R to the Q this is it
now what so this is now how about the

1454
00:40:45,130 --> 00:40:45,140
now what so this is now how about the

1455
00:40:45,140 --> 00:40:48,069
now what so this is now how about the
volume of the unit cell let's find out

1456
00:40:48,069 --> 00:40:48,079
volume of the unit cell let's find out

1457
00:40:48,079 --> 00:40:53,400
volume of the unit cell let's find out
the volume of the unit cell volume of

1458
00:40:53,400 --> 00:40:53,410
the volume of the unit cell volume of

1459
00:40:53,410 --> 00:41:00,640
the volume of the unit cell volume of
the unit cell in this case here to R and

1460
00:41:00,640 --> 00:41:00,650
the unit cell in this case here to R and

1461
00:41:00,650 --> 00:41:05,160
the unit cell in this case here to R and
that is going to be equals to 2 R 2 D

1462
00:41:05,160 --> 00:41:05,170
that is going to be equals to 2 R 2 D

1463
00:41:05,170 --> 00:41:08,890
that is going to be equals to 2 R 2 D
cube right that is the volume now the

1464
00:41:08,890 --> 00:41:08,900
cube right that is the volume now the

1465
00:41:08,900 --> 00:41:12,509
cube right that is the volume now the
packing efficiency will be found by

1466
00:41:12,509 --> 00:41:12,519
packing efficiency will be found by

1467
00:41:12,519 --> 00:41:19,930
packing efficiency will be found by
simply 4 over 3 PI R to the cube divided

1468
00:41:19,930 --> 00:41:19,940
simply 4 over 3 PI R to the cube divided

1469
00:41:19,940 --> 00:41:28,689
simply 4 over 3 PI R to the cube divided
by 2 R to the cube and if I simply this

1470
00:41:28,689 --> 00:41:28,699
by 2 R to the cube and if I simply this

1471
00:41:28,699 --> 00:41:30,430
by 2 R to the cube and if I simply this
is going to be I should probably put

1472
00:41:30,430 --> 00:41:30,440
is going to be I should probably put

1473
00:41:30,440 --> 00:41:36,130
is going to be I should probably put
here multiply that by 100 and this will

1474
00:41:36,130 --> 00:41:36,140
here multiply that by 100 and this will

1475
00:41:36,140 --> 00:41:40,170
here multiply that by 100 and this will
be percent packing efficiency I should

1476
00:41:40,170 --> 00:41:40,180
be percent packing efficiency I should

1477
00:41:40,180 --> 00:41:53,620
be percent packing efficiency I should
percent packing efficiency okay now if

1478
00:41:53,620 --> 00:41:53,630
percent packing efficiency okay now if

1479
00:41:53,630 --> 00:41:58,779
percent packing efficiency okay now if
you work it out those are just the

1480
00:41:58,779 --> 00:41:58,789
you work it out those are just the

1481
00:41:58,789 --> 00:42:01,359
you work it out those are just the
numbers you will simply find out that

1482
00:42:01,359 --> 00:42:01,369
numbers you will simply find out that

1483
00:42:01,369 --> 00:42:11,259
numbers you will simply find out that
will be equal to in this case 52 percent

1484
00:42:11,259 --> 00:42:11,269
will be equal to in this case 52 percent

1485
00:42:11,269 --> 00:42:19,799
will be equal to in this case 52 percent
this is simply equals to 52 percent okay

1486
00:42:19,799 --> 00:42:19,809
this is simply equals to 52 percent okay

1487
00:42:19,809 --> 00:42:26,219
this is simply equals to 52 percent okay
now that simply means if you have a

1488
00:42:26,219 --> 00:42:26,229
now that simply means if you have a

1489
00:42:26,229 --> 00:42:31,299
now that simply means if you have a
metal which have simple cubic lattice

1490
00:42:31,299 --> 00:42:31,309
metal which have simple cubic lattice

1491
00:42:31,309 --> 00:42:38,079
metal which have simple cubic lattice
and simple cubic unit cell and all of

1492
00:42:38,079 --> 00:42:38,089
and simple cubic unit cell and all of

1493
00:42:38,089 --> 00:42:41,699
and simple cubic unit cell and all of
the atoms are touching each other only

1494
00:42:41,699 --> 00:42:41,709
the atoms are touching each other only

1495
00:42:41,709 --> 00:42:47,229
the atoms are touching each other only
52% of the spain's will be full by these

1496
00:42:47,229 --> 00:42:47,239
52% of the spain's will be full by these

1497
00:42:47,239 --> 00:42:48,910
52% of the spain's will be full by these
atoms 48 percent

1498
00:42:48,910 --> 00:42:48,920
atoms 48 percent

1499
00:42:48,920 --> 00:42:54,340
atoms 48 percent
be empty right now if I take the second

1500
00:42:54,340 --> 00:42:54,350
be empty right now if I take the second

1501
00:42:54,350 --> 00:43:00,940
be empty right now if I take the second
case is the let's say face center face

1502
00:43:00,940 --> 00:43:00,950
case is the let's say face center face

1503
00:43:00,950 --> 00:43:07,500
case is the let's say face center face
centered cubic and in this case if I

1504
00:43:07,500 --> 00:43:07,510
centered cubic and in this case if I

1505
00:43:07,510 --> 00:43:12,100
centered cubic and in this case if I
find out the edge of the unit cell in

1506
00:43:12,100 --> 00:43:12,110
find out the edge of the unit cell in

1507
00:43:12,110 --> 00:43:15,720
find out the edge of the unit cell in
terms of the radius of the spheres

1508
00:43:15,720 --> 00:43:15,730
terms of the radius of the spheres

1509
00:43:15,730 --> 00:43:18,700
terms of the radius of the spheres
remember again the face centered I have

1510
00:43:18,700 --> 00:43:18,710
remember again the face centered I have

1511
00:43:18,710 --> 00:43:29,710
remember again the face centered I have
one here like this and I have here here

1512
00:43:29,710 --> 00:43:29,720
one here like this and I have here here

1513
00:43:29,720 --> 00:43:32,770
one here like this and I have here here
and here all touching now this is the

1514
00:43:32,770 --> 00:43:32,780
and here all touching now this is the

1515
00:43:32,780 --> 00:43:41,940
and here all touching now this is the
edge a this is also a now this part here

1516
00:43:41,940 --> 00:43:41,950
edge a this is also a now this part here

1517
00:43:41,950 --> 00:43:45,520
edge a this is also a now this part here
ar-ar-ar-ar radius so what I have here

1518
00:43:45,520 --> 00:43:45,530
ar-ar-ar-ar radius so what I have here

1519
00:43:45,530 --> 00:43:53,710
ar-ar-ar-ar radius so what I have here
for our right angle triangle relation

1520
00:43:53,710 --> 00:43:53,720
for our right angle triangle relation

1521
00:43:53,720 --> 00:43:56,440
for our right angle triangle relation
here for our two the square will be

1522
00:43:56,440 --> 00:43:56,450
here for our two the square will be

1523
00:43:56,450 --> 00:44:02,560
here for our two the square will be
equal to 2a squared right and now how

1524
00:44:02,560 --> 00:44:02,570
equal to 2a squared right and now how

1525
00:44:02,570 --> 00:44:07,930
equal to 2a squared right and now how
many spheres or atoms make a face

1526
00:44:07,930 --> 00:44:07,940
many spheres or atoms make a face

1527
00:44:07,940 --> 00:44:12,970
many spheres or atoms make a face
centered unit cell for right four four

1528
00:44:12,970 --> 00:44:12,980
centered unit cell for right four four

1529
00:44:12,980 --> 00:44:16,510
centered unit cell for right four four
spheres or atoms let's see now

1530
00:44:16,510 --> 00:44:16,520
spheres or atoms let's see now

1531
00:44:16,520 --> 00:44:20,290
spheres or atoms let's see now
that means that volume occupied I can

1532
00:44:20,290 --> 00:44:20,300
that means that volume occupied I can

1533
00:44:20,300 --> 00:44:25,360
that means that volume occupied I can
find out the volume occupied being

1534
00:44:25,360 --> 00:44:25,370
find out the volume occupied being

1535
00:44:25,370 --> 00:44:31,480
find out the volume occupied being
equals to 4 times 4 over 3 PI R to the

1536
00:44:31,480 --> 00:44:31,490
equals to 4 times 4 over 3 PI R to the

1537
00:44:31,490 --> 00:44:36,670
equals to 4 times 4 over 3 PI R to the
cube now if I simply find out the value

1538
00:44:36,670 --> 00:44:36,680
cube now if I simply find out the value

1539
00:44:36,680 --> 00:44:40,300
cube now if I simply find out the value
of I a the edge of the unit in terms of

1540
00:44:40,300 --> 00:44:40,310
of I a the edge of the unit in terms of

1541
00:44:40,310 --> 00:44:42,880
of I a the edge of the unit in terms of
r then I can find out the volume of the

1542
00:44:42,880 --> 00:44:42,890
r then I can find out the volume of the

1543
00:44:42,890 --> 00:44:46,690
r then I can find out the volume of the
unit cell and in this case it will be 4

1544
00:44:46,690 --> 00:44:46,700
unit cell and in this case it will be 4

1545
00:44:46,700 --> 00:44:51,100
unit cell and in this case it will be 4
R square and that is 4 R is equal to

1546
00:44:51,100 --> 00:44:51,110
R square and that is 4 R is equal to

1547
00:44:51,110 --> 00:44:55,560
R square and that is 4 R is equal to
square root 2 a and a is equal to 4 R

1548
00:44:55,560 --> 00:44:55,570
square root 2 a and a is equal to 4 R

1549
00:44:55,570 --> 00:44:59,430
square root 2 a and a is equal to 4 R
divided by square root 2 and B

1550
00:44:59,430 --> 00:44:59,440
divided by square root 2 and B

1551
00:44:59,440 --> 00:45:04,200
divided by square root 2 and B
the volume of the unit cell will be

1552
00:45:04,200 --> 00:45:04,210
the volume of the unit cell will be

1553
00:45:04,210 --> 00:45:06,870
the volume of the unit cell will be
equal to a to the cube and that simply

1554
00:45:06,870 --> 00:45:06,880
equal to a to the cube and that simply

1555
00:45:06,880 --> 00:45:13,820
equal to a to the cube and that simply
means for our to the cube and divided by

1556
00:45:13,820 --> 00:45:13,830
means for our to the cube and divided by

1557
00:45:13,830 --> 00:45:17,160
means for our to the cube and divided by
2 square root to take the clip of that

1558
00:45:17,160 --> 00:45:17,170
2 square root to take the clip of that

1559
00:45:17,170 --> 00:45:18,930
2 square root to take the clip of that
that will be it

1560
00:45:18,930 --> 00:45:18,940
that will be it

1561
00:45:18,940 --> 00:45:39,460
that will be it
now if I simply take the ratio there

1562
00:45:39,460 --> 00:45:39,470

1563
00:45:39,470 --> 00:45:48,580
and it would be again as follow 16 PI R

1564
00:45:48,580 --> 00:45:48,590
and it would be again as follow 16 PI R

1565
00:45:48,590 --> 00:45:53,980
and it would be again as follow 16 PI R
to the cube divided by three and the

1566
00:45:53,980 --> 00:45:53,990
to the cube divided by three and the

1567
00:45:53,990 --> 00:45:59,980
to the cube divided by three and the
whole thing's is divided by 64 R to the

1568
00:45:59,980 --> 00:45:59,990
whole thing's is divided by 64 R to the

1569
00:45:59,990 --> 00:46:02,859
whole thing's is divided by 64 R to the
cube that is this one here and divided

1570
00:46:02,859 --> 00:46:02,869
cube that is this one here and divided

1571
00:46:02,869 --> 00:46:08,200
cube that is this one here and divided
by 2 square root 2 and multiply it by

1572
00:46:08,200 --> 00:46:08,210
by 2 square root 2 and multiply it by

1573
00:46:08,210 --> 00:46:13,180
by 2 square root 2 and multiply it by
hundreds and this would be equals to 74

1574
00:46:13,180 --> 00:46:13,190
hundreds and this would be equals to 74

1575
00:46:13,190 --> 00:46:20,980
hundreds and this would be equals to 74
percent so if you have a phase centered

1576
00:46:20,980 --> 00:46:20,990
percent so if you have a phase centered

1577
00:46:20,990 --> 00:46:23,710
percent so if you have a phase centered
lattice that means the phase centered

1578
00:46:23,710 --> 00:46:23,720
lattice that means the phase centered

1579
00:46:23,720 --> 00:46:27,300
lattice that means the phase centered
unit cells in a metal crystalline metal

1580
00:46:27,300 --> 00:46:27,310
unit cells in a metal crystalline metal

1581
00:46:27,310 --> 00:46:30,240
unit cells in a metal crystalline metal
packing efficiency is much higher than

1582
00:46:30,240 --> 00:46:30,250
packing efficiency is much higher than

1583
00:46:30,250 --> 00:46:35,349
packing efficiency is much higher than
when you have a simple cubic thing and

1584
00:46:35,349 --> 00:46:35,359
when you have a simple cubic thing and

1585
00:46:35,359 --> 00:46:37,510
when you have a simple cubic thing and
actually remember we said that one of

1586
00:46:37,510 --> 00:46:37,520
actually remember we said that one of

1587
00:46:37,520 --> 00:46:41,290
actually remember we said that one of
those closed packing structures have the

1588
00:46:41,290 --> 00:46:41,300
those closed packing structures have the

1589
00:46:41,300 --> 00:46:43,960
those closed packing structures have the
unit cell phase centered unit cell and

1590
00:46:43,960 --> 00:46:43,970
unit cell phase centered unit cell and

1591
00:46:43,970 --> 00:46:45,430
unit cell phase centered unit cell and
that's why we have the face centered

1592
00:46:45,430 --> 00:46:45,440
that's why we have the face centered

1593
00:46:45,440 --> 00:46:46,870
that's why we have the face centered
yourself because the face center unit

1594
00:46:46,870 --> 00:46:46,880
yourself because the face center unit

1595
00:46:46,880 --> 00:46:49,930
yourself because the face center unit
cell allows you to pack the same size

1596
00:46:49,930 --> 00:46:49,940
cell allows you to pack the same size

1597
00:46:49,940 --> 00:46:52,650
cell allows you to pack the same size
fares with a maximum packing efficiency

1598
00:46:52,650 --> 00:46:52,660
fares with a maximum packing efficiency

1599
00:46:52,660 --> 00:46:55,030
fares with a maximum packing efficiency
that means to put the maximum number of

1600
00:46:55,030 --> 00:46:55,040
that means to put the maximum number of

1601
00:46:55,040 --> 00:46:58,150
that means to put the maximum number of
spheres in a given volume now you can

1602
00:46:58,150 --> 00:46:58,160
spheres in a given volume now you can

1603
00:46:58,160 --> 00:47:03,839
spheres in a given volume now you can
calculate this for the body centered

1604
00:47:03,839 --> 00:47:03,849
calculate this for the body centered

1605
00:47:03,849 --> 00:47:07,000
calculate this for the body centered
cubic lattice and body centered cubic

1606
00:47:07,000 --> 00:47:07,010
cubic lattice and body centered cubic

1607
00:47:07,010 --> 00:47:09,460
cubic lattice and body centered cubic
unit just the same fashion let's say

1608
00:47:09,460 --> 00:47:09,470
unit just the same fashion let's say

1609
00:47:09,470 --> 00:47:15,070
unit just the same fashion let's say
body centered body centered cubic

1610
00:47:15,070 --> 00:47:15,080
body centered body centered cubic

1611
00:47:15,080 --> 00:47:19,660
body centered body centered cubic
lattice in that case the number of

1612
00:47:19,660 --> 00:47:19,670
lattice in that case the number of

1613
00:47:19,670 --> 00:47:24,010
lattice in that case the number of
spheres is how many to write one coming

1614
00:47:24,010 --> 00:47:24,020
spheres is how many to write one coming

1615
00:47:24,020 --> 00:47:26,800
spheres is how many to write one coming
from the corners and one coming from the

1616
00:47:26,800 --> 00:47:26,810
from the corners and one coming from the

1617
00:47:26,810 --> 00:47:28,870
from the corners and one coming from the
center because that belongs to the the

1618
00:47:28,870 --> 00:47:28,880
center because that belongs to the the

1619
00:47:28,880 --> 00:47:30,310
center because that belongs to the the
whole of them belongs to the unit cell

1620
00:47:30,310 --> 00:47:30,320
whole of them belongs to the unit cell

1621
00:47:30,320 --> 00:47:36,550
whole of them belongs to the unit cell
so two spheres that simply means volume

1622
00:47:36,550 --> 00:47:36,560
so two spheres that simply means volume

1623
00:47:36,560 --> 00:47:42,450
so two spheres that simply means volume
occupied would be equal to 2 times 4

1624
00:47:42,450 --> 00:47:42,460
occupied would be equal to 2 times 4

1625
00:47:42,460 --> 00:47:49,000
occupied would be equal to 2 times 4
over 3 PI R to the cube right now how

1626
00:47:49,000 --> 00:47:49,010
over 3 PI R to the cube right now how

1627
00:47:49,010 --> 00:47:53,140
over 3 PI R to the cube right now how
about the volume of the cube

1628
00:47:53,140 --> 00:47:53,150
about the volume of the cube

1629
00:47:53,150 --> 00:47:59,380
about the volume of the cube
now that is a little bit more difficult

1630
00:47:59,380 --> 00:47:59,390
now that is a little bit more difficult

1631
00:47:59,390 --> 00:48:01,989
now that is a little bit more difficult
to see the relationship between the

1632
00:48:01,989 --> 00:48:01,999
to see the relationship between the

1633
00:48:01,999 --> 00:48:04,450
to see the relationship between the
radius and the edge of the unit cell for

1634
00:48:04,450 --> 00:48:04,460
radius and the edge of the unit cell for

1635
00:48:04,460 --> 00:48:11,200
radius and the edge of the unit cell for
the body-centered unit cell cubic unit

1636
00:48:11,200 --> 00:48:11,210
the body-centered unit cell cubic unit

1637
00:48:11,210 --> 00:48:15,089
the body-centered unit cell cubic unit
cell you can have this right angle

1638
00:48:15,089 --> 00:48:15,099
cell you can have this right angle

1639
00:48:15,099 --> 00:48:23,230
cell you can have this right angle
triangle like this now this is the edge

1640
00:48:23,230 --> 00:48:23,240
triangle like this now this is the edge

1641
00:48:23,240 --> 00:48:25,630
triangle like this now this is the edge
of the unit cell one edge of the inner

1642
00:48:25,630 --> 00:48:25,640
of the unit cell one edge of the inner

1643
00:48:25,640 --> 00:48:26,079
of the unit cell one edge of the inner
self

1644
00:48:26,079 --> 00:48:26,089
self

1645
00:48:26,089 --> 00:48:31,809
self
now this one is buddy diagonal body

1646
00:48:31,809 --> 00:48:31,819
now this one is buddy diagonal body

1647
00:48:31,819 --> 00:48:36,430
now this one is buddy diagonal body
diagonal what does that mean that means

1648
00:48:36,430 --> 00:48:36,440
diagonal what does that mean that means

1649
00:48:36,440 --> 00:48:41,130
diagonal what does that mean that means
it goes from one side of the cube and

1650
00:48:41,130 --> 00:48:41,140
it goes from one side of the cube and

1651
00:48:41,140 --> 00:48:45,150
it goes from one side of the cube and
passes comes to right across to this

1652
00:48:45,150 --> 00:48:45,160
passes comes to right across to this

1653
00:48:45,160 --> 00:48:48,130
passes comes to right across to this
corner here so that is the body center

1654
00:48:48,130 --> 00:48:48,140
corner here so that is the body center

1655
00:48:48,140 --> 00:48:49,870
corner here so that is the body center
which goes through the center of the

1656
00:48:49,870 --> 00:48:49,880
which goes through the center of the

1657
00:48:49,880 --> 00:48:54,069
which goes through the center of the
cube actually and this one is actually

1658
00:48:54,069 --> 00:48:54,079
cube actually and this one is actually

1659
00:48:54,079 --> 00:48:57,339
cube actually and this one is actually
this part is a face centered face

1660
00:48:57,339 --> 00:48:57,349
this part is a face centered face

1661
00:48:57,349 --> 00:49:07,799
this part is a face centered face
diagonal this is let's say face diagonal

1662
00:49:07,799 --> 00:49:07,809

1663
00:49:07,809 --> 00:49:12,789
and this one is the body diagram now in

1664
00:49:12,789 --> 00:49:12,799
and this one is the body diagram now in

1665
00:49:12,799 --> 00:49:14,440
and this one is the body diagram now in
the body diagonal we have one in the

1666
00:49:14,440 --> 00:49:14,450
the body diagonal we have one in the

1667
00:49:14,450 --> 00:49:18,029
the body diagonal we have one in the
center like this and we have the other

1668
00:49:18,029 --> 00:49:18,039
center like this and we have the other

1669
00:49:18,039 --> 00:49:21,759
center like this and we have the other
three cubes our spares are touching each

1670
00:49:21,759 --> 00:49:21,769
three cubes our spares are touching each

1671
00:49:21,769 --> 00:49:23,529
three cubes our spares are touching each
other so that means that this body

1672
00:49:23,529 --> 00:49:23,539
other so that means that this body

1673
00:49:23,539 --> 00:49:27,900
other so that means that this body
diagonal D is equal to 4 R now this

1674
00:49:27,900 --> 00:49:27,910
diagonal D is equal to 4 R now this

1675
00:49:27,910 --> 00:49:30,700
diagonal D is equal to 4 R now this
let's call that B which is the face

1676
00:49:30,700 --> 00:49:30,710
let's call that B which is the face

1677
00:49:30,710 --> 00:49:34,569
let's call that B which is the face
diagonal face diagonal square of face

1678
00:49:34,569 --> 00:49:34,579
diagonal face diagonal square of face

1679
00:49:34,579 --> 00:49:39,160
diagonal face diagonal square of face
diagonal is equal to 2a squared and from

1680
00:49:39,160 --> 00:49:39,170
diagonal is equal to 2a squared and from

1681
00:49:39,170 --> 00:49:42,849
diagonal is equal to 2a squared and from
here I can simply write down this

1682
00:49:42,849 --> 00:49:42,859
here I can simply write down this

1683
00:49:42,859 --> 00:49:46,239
here I can simply write down this
relationship the square of this body

1684
00:49:46,239 --> 00:49:46,249
relationship the square of this body

1685
00:49:46,249 --> 00:49:51,069
relationship the square of this body
diagonal which is 4 R square would be

1686
00:49:51,069 --> 00:49:51,079
diagonal which is 4 R square would be

1687
00:49:51,079 --> 00:49:53,979
diagonal which is 4 R square would be
equal to square of this which is a

1688
00:49:53,979 --> 00:49:53,989
equal to square of this which is a

1689
00:49:53,989 --> 00:49:56,589
equal to square of this which is a
square plus the square of this which is

1690
00:49:56,589 --> 00:49:56,599
square plus the square of this which is

1691
00:49:56,599 --> 00:50:00,519
square plus the square of this which is
equal to that face diagonal 2b squared

1692
00:50:00,519 --> 00:50:00,529
equal to that face diagonal 2b squared

1693
00:50:00,529 --> 00:50:02,769
equal to that face diagonal 2b squared
and from that you can find out the

1694
00:50:02,769 --> 00:50:02,779
and from that you can find out the

1695
00:50:02,779 --> 00:50:06,860
and from that you can find out the
relationship between simply R and a

1696
00:50:06,860 --> 00:50:06,870
relationship between simply R and a

1697
00:50:06,870 --> 00:50:12,100
relationship between simply R and a
and find out the volume occupied and

1698
00:50:12,100 --> 00:50:12,110
and find out the volume occupied and

1699
00:50:12,110 --> 00:50:15,740
and find out the volume occupied and
volume of the unit cell in this case you

1700
00:50:15,740 --> 00:50:15,750
volume of the unit cell in this case you

1701
00:50:15,750 --> 00:50:25,990
volume of the unit cell in this case you
end up with 68% packing efficiency

1702
00:50:25,990 --> 00:50:26,000

1703
00:50:26,000 --> 00:50:33,230
efficiency is 68% you see again these

1704
00:50:33,230 --> 00:50:33,240
efficiency is 68% you see again these

1705
00:50:33,240 --> 00:50:36,920
efficiency is 68% you see again these
simply shows you that the phase centered

1706
00:50:36,920 --> 00:50:36,930
simply shows you that the phase centered

1707
00:50:36,930 --> 00:50:42,580
simply shows you that the phase centered
cubic unit cell allows you to get the

1708
00:50:42,580 --> 00:50:42,590
cubic unit cell allows you to get the

1709
00:50:42,590 --> 00:50:46,670
cubic unit cell allows you to get the
maximum packing efficiency if you have

1710
00:50:46,670 --> 00:50:46,680
maximum packing efficiency if you have

1711
00:50:46,680 --> 00:50:49,960
maximum packing efficiency if you have
that and that's why actually as I said

1712
00:50:49,960 --> 00:50:49,970
that and that's why actually as I said

1713
00:50:49,970 --> 00:50:53,990
that and that's why actually as I said
the unit cell of one of the closest pack

1714
00:50:53,990 --> 00:50:54,000
the unit cell of one of the closest pack

1715
00:50:54,000 --> 00:50:56,320
the unit cell of one of the closest pack
structure is the phase centered cubic

1716
00:50:56,320 --> 00:50:56,330
structure is the phase centered cubic

1717
00:50:56,330 --> 00:50:59,620
structure is the phase centered cubic
unit cells they Center cubic in yourself

1718
00:50:59,620 --> 00:50:59,630
unit cells they Center cubic in yourself

1719
00:50:59,630 --> 00:51:03,380
unit cells they Center cubic in yourself
ok any questions