One mole crystal of a metal halide of the type MX with molecular...

One mole crystal of a metal halide of the type $\text{MX}$ with molecular weight $\text{119}\text{g}$ having face centered cubic structure with unit cell length $\text{6}\text{.58}\text{Å}$ was recrystallized. The density of the recrystallized crystal was found to be $2.44gcm^{- 3}$. The type of defect introduced during the recrystalization may be