Two unit cells can be used to describe an NaCl-type structure. They are the same size and shape, but they differ in the location of the lattice points used to define the cell. In one cell, lattice points are placed at the centers of the anions. This cell has anions at the corners and in the centers of the faces.

In the alternate unit cell, the lattice points are placed at the centers of the cations. The alternate unit cell has cations at the corners and in the centeres of the faces.

Click the links on the right to view the two NaCl unit cell types.