Materials Data on Tm2O3 by Materials Project

Tm2O3 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Tm3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tm–O bond distances ranging from 2.17–2.54 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Tm3+ atoms to form OTm4 tetrahedra that share corners with six equivalent OTm6 octahedra, corners with six equivalent OTm4 tetrahedra, edges with three equivalent OTm6 octahedra, and edges with three equivalent OTm4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–55°. In the second O2- site, O2- is bonded to six equivalent Tm3+ atoms to form OTm6 octahedra that share corners with twelve equivalent OTm4 tetrahedra, edges with six equivalent OTm6 octahedra, and edges with six equivalent OTm4 tetrahedra.