Density of a unit cell is the same as the density of the substances. So, if the density…

Density of a unit cell is the same as the density of the substances. So, if the density of the substance is known, we can calculate the number of atoms or dimesions of the unit cell. The density of the unit cell is related to its mass (M), number of atoms per unit cell (Z), edge length (a in cm), and Avogadro’s constant N_A as :
\(\rho=\frac{\mathrm{Z} \times \mathrm{M}}{\mathrm{a}^{3} \times \mathrm{N}_{\mathrm{A}}}\) 
A metal A (atomic mass = 60) has a body - centered cubic crystal structure. The density of the metal is 4.2 g cm^–3. The volume of unit cell is