Question

In a solid, oxide ions are arranged in ccp. Cations '$A$' occupy one-sixth of the tetrahedral voids and cations '$B$' occupy one-third of the octahedral voids. Which of the following is the correct formula of the oxide?

• A. $ABO_{3}$
• B. $A_{2}BO_{3}$
• C. $AB_{2}O_{3}$
• D. None of these

Answer 1

Answer: (A)

Cation $A=\frac{1}{6}\times 8=\frac{8}{6}=\frac{4}{3}$
Cation $B=\frac{1}{3}\times 4=\frac{4}{3}$
$O^{2 -}=8\times \frac{1}{8}+6\times \frac{1}{2}=4$
$A : B : O^{2 -}=\frac{4}{3}:\frac{4}{3}:4=1:1:3$