Materials Data on Ho3TaO7 by Materials Project

Abstract

Ho3TaO7 crystallizes in the orthorhombic Cmme space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six O2- atoms to form distorted corner-sharing HoO6 octahedra. The corner-sharing octahedral tilt angles are 70°. There are two shorter (2.26 Å) and four longer (2.27 Å) Ho–O bond lengths. In the second Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ho–O bond distances ranging from 2.08–2.56 Å. Ta5+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.16 Å) and four longer (2.18 Å) Ta–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ho3+ atoms to form OHo4 tetrahedra that share corners with ten OHo4 tetrahedra and edges with four equivalent OHo3Ta tetrahedra. In the second O2- site, O2- is bonded to three Ho3+ and one Ta5+ atom to form a mixture of distorted edge and corner-sharing OHo3Ta tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+ and two equivalent Ta5+ atoms.