Materials Data on Tm2GeO5 by Materials Project

Abstract

Tm2GeO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Tm3+ sites. In the first Tm3+ site, Tm3+ is bonded to seven O2- atoms to form distorted TmO7 hexagonal pyramids that share corners with two equivalent TmO7 hexagonal pyramids, corners with three equivalent GeO5 trigonal bipyramids, edges with five TmO7 hexagonal pyramids, and edges with two equivalent GeO5 trigonal bipyramids. There are a spread of Tm–O bond distances ranging from 2.25–2.37 Å. In the second Tm3+ site, Tm3+ is bonded to seven O2- atoms to form distorted TmO7 hexagonal pyramids that share corners with two equivalent TmO7 hexagonal pyramids, a cornercorner with one GeO5 trigonal bipyramid, edges with seven TmO7 hexagonal pyramids, and edges with two equivalent GeO5 trigonal bipyramids. There are a spread of Tm–O bond distances ranging from 2.29–2.35 Å. Ge4+ is bonded to five O2- atoms to form distorted GeO5 trigonal bipyramids that share corners with four TmO7 hexagonal pyramids, corners with two equivalent GeO5 trigonal bipyramids, and edges with four TmO7 hexagonal pyramids. There are a spread of Ge–O bond distances ranging from 1.76–1.94 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Tm3+ atoms to form OTm4 tetrahedra that share corners with fourteen OTm4 tetrahedra and edges with four OTm3Ge tetrahedra. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Tm3+ and one Ge4+ atom. In the third O2- site, O2- is bonded to two Tm3+ and two equivalent Ge4+ atoms to form distorted OTm2Ge2 tetrahedra that share corners with six OTm4 tetrahedra and edges with five OTm3Ge tetrahedra. In the fourth O2- site, O2- is bonded to three Tm3+ and one Ge4+ atom to form OTm3Ge tetrahedra that share corners with nine OTm4 tetrahedra and edges with four OTm3Ge tetrahedra. In the fifth O2- site, O2- is bonded to three Tm3+ and one Ge4+ atom to form a mixture of distorted edge and corner-sharing OTm3Ge tetrahedra.