Perovskites and Antiperovskites. Mineralogical Fairy Tale

Classical crystal chemistry describes various compounds based on cation-centered polyhedra and their complexes. However, there are a number of compounds with the so-called “additional” anion in the structure, which occupies a separate position, i.e. it is not boned to a high-valent cation and is not a part either of tetrahedra or octahedra. So, such structures are better explained on the basis of anion-centered polyhedral, as their physical properties directly depend on the distribution of chemical bonds in their structure. We have already described compounds with anti-tetrahedra with oxygen atoms in the center and cations at the corners of a tetrahedron. This paper describes sulfates, phosphates, and silicates with octahedrons with Cl, F, or O anions at the center and cations at the vertices. These minerals contain antiperovskite fragments and are conventionally called antiperovskites.

cation-centered polyhedral, antiperovskite structures, anion-centered units, perovskite