Question

In a solid, oxide ions are arranged in hcp. One-third of octahedral voids are occupied by the cations A and one-sixth of the tetrahedral voids are occupied by the cations B. What is the formula of the compound?

Answer 1

Effective number of oxide ions $\Rightarrow Z_{O^2}=6$

Effective number of cation $A\Rightarrow Z_A=\frac{1}{3}\times$ Octahedral voids $=\frac{1}{3}\times 6=2$

Effective number of cation $B\Rightarrow Z_B=\frac{1}{6}\times$ Tetrahedral voids $=\frac{1}{6}\times 12=2$

Formula of the compound $\Rightarrow A_2{B}_2{O}_6=AB{O}_3$