Solid State Question 256
Question: A crystalline solid is made of X, Y and Z. Atoms of X are present in ccp lattice; Y occupies all the octahedral voids and Z occupies all the tetrahedral voids. If all atoms along with body are diagonally removed then formula of solid will be:
Options:
A) $ X_5Y_4Z_8 $
B) $ X_8Y_4Z_5 $
C) $ X_2YZ_2 $
D) $ XYZ_2 $
Show Answer
Answer:
Correct Answer: A
Solution:
[a] Number of X-atoms in unit cell = 4 (ccp) Number of Y-atoms=4 Number of Z-atoms=8 If atoms along one body diagonal are removed then 2X, 1Y and 2Z atoms will be absent. Effective number of atoms may be calculated as $ X=4-( 2\times \frac{1}{8} )=\frac{15}{4} $
$ Y=4-1=3 $
$ z=8-2=6 $ Simplest ratio Simplest formula $ =X_5Y_4Z_8 $
BETA
