What is the number of octahedral voids present in $0.2 \ mol$ of a compound forming $hcp$ structure?

Calculate the volume occupied by all particles in an $fcc$ unit cell if the volume of the unit cell is $1.6 \times 10^{-23} \ cm^3$.

In a compound,nitrogen atoms $(N)$ make a cubic close-packed lattice and metal atoms $(M)$ occupy one-third of the tetrahedral voids present. Determine the formula of the compound formed by $M$ and $N$.

Atoms of element $B$ form $hcp$ lattice and those of the element $A$ occupy $2/3$ of tetrahedral voids. What is the formula of the compound formed by the elements $A$ and $B$?

If the number of atoms in a unit cell is $2$,then the number of tetrahedral and octahedral voids will be ....... and ....... respectively.

$A$ compound is formed by two elements $A$ and $B$. The atoms of element $B$ form $ccp$ structure. The atoms of $A$ occupy $1/3$ of tetrahedral voids. What is the formula of the compound?