Materials Data on HoTa7O19 by Materials Project

Abstract

HoTa7O19 crystallizes in the hexagonal P-6c2 space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are six shorter (2.40 Å) and two longer (2.63 Å) Ho–O bond lengths. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ta–O bond distances ranging from 1.93–2.46 Å. In the second Ta5+ site, Ta5+ is bonded in an octahedral geometry to six equivalent O2- atoms. All Ta–O bond lengths are 2.01 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ho3+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+ and three equivalent Ta5+ atoms.