Length of edge of the unit cell = 412.1 pm, = 412.1 × 10−10 cm Volume of the unit cell = (412.1×10−10)3 = 7.00 × 10−23cm^3$$ Formula mass of caesium chloride = 168.5 a.m.u The number of formula units per unit cell of caesium chloride is 1 as it has bodycentered cubic lattice. ∴ Z = 1 formula units / unit cell Density = Formula mass × Z / unit cell volume (cm)3 × Navo =