This nomenclature now denotes a variety of compounds with the same type of crystal structure as CaTiO 3 and the general chemical formula ABX 3 , in which a B-site cation is coordinated by six X-site anions to form a [BX 6 ] octahedron and an A-site cation is implanted in the void surrounded by eight cornershared [BX 6 ] octahedra