What is "antiperovskite"

n. (context mineral English) Any crystal with a structure based on a perovskite but with the cations replaced by anions and vice versa.

The antiperovskite crystal structure is similar to the perovskite structure that is common in nature. The key difference is that the positions of the cation and anion constituents are reversed in the unit cell structure. As opposed to perovskite, antiperovskite consists of one anion coordinated with two types cations that bond with both. Antiperovskite compounds are an important class of materials since synthesized antiperovskites demonstrate interesting and useful physical properties.