the zinc-blende structure

The zinc-blende structure, named after the mineral sphalerite (cubic zinc sulfide), is the diamond structure with two kinds of atom instead of one. Every atom is bonded to four neighbours of the opposite type sitting at the corners of a tetrahedron. It is the master structure of the semiconductor world.

Build it from close packing: take an FCC array of sulfur atoms and drop zinc atoms into half of the eight tetrahedral holes, choosing an alternating set so that each zinc is surrounded by four sulfurs and each sulfur by four zincs. Both species therefore have coordination number 4, and the cubic cell contains 4 formula units of ZnS. The framework of atomic positions is exactly that of diamond cubic; zinc blende just colours the two interpenetrating FCC sublattices with different elements.

This is the structure of most of the technologically vital compound semiconductors: the III-V family such as gallium arsenide, indium phosphide, and gallium antimonide, and the II-VI family such as zinc selenide and cadmium telluride, plus cubic silicon carbide. Because the two sublattices hold different atoms, the structure lacks a centre of inversion (it is non-centrosymmetric), which is precisely why these crystals can be piezoelectric and show strong nonlinear optical effects.