Materials Data on Ca3Bi2O7 by Materials Project

Abstract

Ca3Bi2O7 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.84 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.28–2.76 Å. Bi4+ is bonded to six O2- atoms to form corner-sharing BiO6 octahedra. The corner-sharing octahedra tilt angles range from 39–47°. There are a spread of Bi–O bond distances ranging from 2.23–2.32 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ca2+ and one Bi4+ atom to form distorted OCa3Bi tetrahedra that share corners with six equivalent OCa3Bi tetrahedra and a cornercorner with one OCa2Bi2 trigonal pyramid. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Bi4+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two equivalent Bi4+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Ca2+ and two equivalent Bi4+ atoms to form distorted OCa2Bi2 trigonal pyramids that share corners with two equivalent OCa3Bi tetrahedra and corners with two equivalent OCa2Bi2 trigonal pyramids.