chalcopyritetype

Chalcopyrite-type refers to a crystal-structure class used by a broad family of ABX2 compounds in which two distinct cations occupy different tetrahedral sites within a zinc blende–derived anion framework X. The prototype is chalcopyrite, CuFeS2. In this tetragonal structure, the A and B cations are ordered on alternating tetrahedral sublattices along the c axis, resulting in a doubling of the zinc blende cell and a space group of I-42d (No. 122). Each X atom is tetrahedrally coordinated by four cations, and the lattice is described by two parameters a and c, with c typically about twice a, though exact ratios vary.

The chalcopyrite-type family covers ABX2 compounds where A and B differ in size or charge and X is a chalcogen (S, Se, Te) or, less commonly, a halide. These materials are direct-band-gap semiconductors with a range of band gaps, and they are extensively studied for optoelectronic applications, especially photovoltaics.

Common examples include CuInSe2, CuGaSe2, CuInS2, and CuGaS2, which in practice form solid solutions over wide composition ranges. The structure also underpins related derivatives such as the stannite and kesterite families, which retain the tetragonal chalcopyrite framework but feature different cation ordering.

In nature, chalcopyrite CuFeS2 is a major ore mineral and the original archetype of the structure. Overall, chalcopyrite-type denotes a tetragonal, zinc blende–derived ABX2 framework with ordered cations and substantial technological relevance in semiconductor science.