Question

Determine the simplest formula of an ionic compound in which cations are present at the corners and the anions occur at the center of each face.

Answer 1

Let cations be A. There are 8 corners. Contribution of eah corner is $\frac{1}{8}$. Total A atom is $\frac{1}{8}\times 8=1$.

Let anions be B. There are 6 faces. Contribution of each phase is $\frac{1}{2}$. Total B atom is $\frac{1}{2}\times 6=3$.

Formula is $A{B}_3$.