V ¼ 4 Â
4
3
p 1.000
ð
Þ
3 þ 0.414
ð
Þ
3 þ 2 Â 0.225
ð
Þ
3
h
i
¼ 18.319
Therefore, the void space is obtained as
Void space ¼ Total volume À occupied volume
¼ 16
ffiffi ffi
2
p À 18.319 ¼ 4.308 ¼ 19 %
Multiple Choice Questions (MCQ)
1. In a plane oblique lattice with a = 3Å, b = 2Å and u = 75°, a translation vector
is given by ~ t ¼ 4~ a þ 5 ~ b, its magnitude is:
(a) 17.50Å
(b) 18.50Å
(c) 19.50Å
(d) 20.50Å
2. In a plane oblique lattice with a = 3Å, b = 2Å and u = 75°, a translation vector
is given by ~ t ¼ 4~ a þ 5 ~ b, its direction is
(a) [3 5]
(b) [4 5]
(c) [5 5]
(d) [6 5]
3. In a plane rectangular lattice with a = 3Å, b = 2Å and u = 90°, a translation
vector is given by ~ t ¼ 4~ a þ 7 ~ b, its magnitude is:
(a) 17.44Å
(b) 18.44Å
(c) 19.44Å
(d) 20.44Å
4. In a plane rectangular lattice with a = 3Å, b = 2Å and u = 90°, a translation
vector is given by ~ t ¼ 4~ a þ 7 ~ b, its direction is:
(a) [3 5]
(b) [4 5]
(c) [4 6]
(d) [4 7]
34
1 Unit Cell Composition