Materials Data on Pm2O3 by Materials Project

Abstract

Pm2O3 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Pm3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pm–O bond distances ranging from 2.30–2.67 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Pm3+ atoms to form OPm4 tetrahedra that share corners with six equivalent OPm6 octahedra, corners with six equivalent OPm4 tetrahedra, edges with three equivalent OPm6 octahedra, and edges with three equivalent OPm4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–56°. In the second O2- site, O2- is bonded to six equivalent Pm3+ atoms to form OPm6 octahedra that share corners with twelve equivalent OPm4 tetrahedra, edges with six equivalent OPm6 octahedra, and edges with six equivalent OPm4 tetrahedra.