Crystal structure of sodium chloride, illustration. Sodium chloride (NaCl) crystallizes in cubic structure (left), with alternating rows of sodium cations (Na+, grey) and chloride anions (Cl?? green). The unit cell (right) has one-fourth of a sodium ion along each edge of the cube. The lattice also has one full chloride ion at the centre of the cell, one-eighth at each of the corners, and one-half a chloride ion in each face. Combined, each unit cell contains three units of NaCl.