DOI: 10.17188/1283171
title: Materials Data on Ho3TaO7 by Materials Project

description: Ho3TaO7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six O2- atoms to form distorted HoO6 octahedra that share corners with two equivalent HoO6 octahedra and corners with two TaO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of Ho–O bond distances ranging from 2.16–2.40 Å. In the second Ho3+ site, Ho3+ is bonded to six O2- atoms to form distorted HoO6 octahedra that share corners with two equivalent HoO6 octahedra and corners with two TaO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of Ho–O bond distances ranging from 2.17–2.41 Å. In the third Ho3+ site, Ho3+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Ho–O bond distances ranging from 2.15–2.72 Å. In the fourth Ho3+ site, Ho3+ is bonded in a 5-coordinate geometry to seven O2- atoms. There are a spread of Ho–O bond distances ranging from 2.15–2.80 Å. In the fifth 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 2.13–2.71 Å. In the sixth 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 2.13–2.68 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to four O2- atoms to form distorted TaO4 tetrahedra that share corners with two HoO6 octahedra and a cornercorner with one TaO5 tetrahedra. The corner-sharing octahedra tilt angles range from 60–63°. There is two shorter (1.90 Å) and two longer (1.91 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 tetrahedra that share corners with two HoO6 octahedra and a cornercorner with one TaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–63°. There are a spread of Ta–O bond distances ranging from 1.90–2.47 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ho3+ atoms to form corner-sharing OHo4 tetrahedra. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ho3+ atoms. In the third O2- site, O2- is bonded to four Ho3+ atoms to form corner-sharing OHo4 tetrahedra. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two Ho3+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ho3+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+ and two Ta5+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to three Ho3+ atoms. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one Ta5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ho3+ and one Ta5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to three Ho3+ atoms.