Question

Element ‘B’ forms ccp structure and ‘A’ occupies half of the octahedral voids, while oxygen atoms occupy all the tetrahedral voids. The structure of bimetallic oxide is:

• A. $A_2{B}_{2}O$
• B. $A{B}_2{O}_4$
• C. $A_4{B}_{2}O$
• D. $A_{2}B{O}_4$

Answer 1

The correct option is B $A{B}_2{O}_4$

Bimetallic oxide has a ccp structure (FCC unit cell). It has both octahedral voids and tetrahedral voids.

Atom B are present at the corner and the face of the unit cell. So the number of B atoms per unit cell $=8\times \frac{1}{8}+6\times \frac{1}{2}=4$

Number of octahedral voids = 4

A atoms present per unit cell $=\frac{1}{2}\times 4=2$

Number of tetrahedral voids = 8

Oxygen atoms present per unit cell= 8

Formula $=A_2{B}_4{O}_8=A{B}_2{O}_4$