Compute the percentage void space per unit volume of unit cell in zinc fluoride structure.
(D). Anions occupy fcc positions and half of the tetrahedral holes are occupied by cations. Since there are four anions and 8 tetrahedral holes per unit cell, the fraction of volume occupied by spheres per unit volume of the unit cell is
for tetrahedral holes,
Void volume = 1 – 0.7493 = 0.2507/unit volume of unit cell.
% void space = 25.07%