Identify the defect that develops when the ratio of number of cations to anions become different from that indicated by its chemical formula.

The mass of an atom present in unit cell is $4.4 \times 10^{-23} \mathrm{~g}$ and the product of density and volume of unit cell is $1.792 \times 10^{-22} \mathrm{~g}$. What is the type of cubic unit cell?

Calculate the total number of tetrahedral and octahedral voids in 0.4 mol compound having such voids in it.

Calculate the volume occupied by a particle in bcc unit cell if the volume of unit cell is $8.2 \times 10^{-23} \mathrm{~cm}^3$.