Sodium Chloride is an alkali halide with an fcc crystal structure. The basis is two ions, a sodium cation and a chlorine anion. The crystal lattice parameter is 0.563 nm. The diagram shows both a unit ...

Zinc sulphide exists with two different crystal structures, the cubic zinc blend (top diagram) and the hexagonal Wurtzite (lower diagram). In the zinc blend structure the sulphur ions form an fcc ...

Therefore, there are eight tetrahedral holes inside each cube. Since the stoichiometry of the salt is 2:1, we must fill all of the tetrahedral holes (the FCC structure gives four selenides, thus we ...