In an ionic solid,anions $(B)$ are arranged in an $hcp$ array and cations $(A)$ occupy $\frac{2}{3}$ of the octahedral voids. What is the formula of the ionic compound?

Calculate the total volume of a simple cubic unit cell in $\text{cm}^3$ if the void volume is $2.0 \times 10^{-23} \text{cm}^3$.

In the closest packing of atoms,

In a crystalline solid with the formula $AB_2O_4$,the oxide ions are arranged in a cubic close-packed $(CCP)$ lattice,while the cations $A$ are present in tetrahedral voids and cations $B$ are present in octahedral voids. What are the percentages of tetrahedral and octahedral voids occupied by $A$ and $B$ respectively?

The volume occupied by the atoms in a unit cell of hexagonal close packing $(HCP)$ or cubic close packing $(CCP)$ is equal to:

The anions $(A)$ of a $C_{p}A_{q}$ molecule form an $fcc$ lattice. Cations $(C)$ are positioned at the body center and half of the edge centers. The formula of the molecule is: