Sphalerite/zincblende structure

Another structure of stoichiometry MX is the sphalerite structure, also known as the zincblende structure.

The names are from a particular mineral form of ZnS.

This structure is regarded as a fcc cubic structure of anions with cations occupying half the tetrahedral holes. It can also be regarded as a fcc cubic structure of cations with anions occupying half the tetrahedral holes.

But the easiest way to remember is to relate it to the structure of diamond:

This is called a diamond cubic structure. It is a face-centered cubic structure with four extra lattice points inside. The zincblende structure is just diamond cubic with alternating atoms, A bonded to four X, and X bonded to four A.

Zinc sulfide is the main form of zinc found in nature. It can be produce by burning zinc and sulphur. It is also insoluble, and will precipitate out if zinc and sulphide ions are in a solution. It gives off visible light when exposed to x-rays or electron beams.

Sphalerite/zincblende is the most stable crystal form of ZnS, but it can also exist in a Wurtzite structure, described next post.