Materials Data on CaTm2O4 by Materials Project

Abstract

CaTm2O4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.97 Å. Tm3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TmO6 octahedra. The corner-sharing octahedra tilt angles range from 0–58°. There are a spread of Tm–O bond distances ranging from 2.18–2.33 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted square co-planar geometry to two equivalent Ca2+ and four equivalent Tm3+ atoms. In the second O2- site, O2- is bonded to two equivalent Ca2+ and two equivalent Tm3+ atoms to form OCa2Tm2 tetrahedra that share corners with two equivalent OCa2Tm2 tetrahedra, corners with ten equivalent OCa2Tm3 trigonal bipyramids, and edges with two equivalent OCa2Tm3 trigonal bipyramids. In the third O2- site, O2- is bonded to two equivalent Ca2+ and three equivalent Tm3+ atoms to form distorted OCa2Tm3 trigonal bipyramids that share corners with five equivalent OCa2Tm2 tetrahedra, corners with two equivalent OCa2Tm3 trigonal bipyramids, an edgeedge with one OCa2Tm2 tetrahedra, and edges with five equivalent OCa2Tm3 trigonal bipyramids.