10.17188/1306544
None Available
Materials Data on HoTa3O9 by Materials Project
LBNL Materials Project; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
2020
Specialized Mix
36 MATERIALS SCIENCE
crystal structure
HoTa3O9
Ho-O-Ta
The Materials Project
2020
en
HoTa3O9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ho3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ho–O bond distances ranging from 2.34–2.69 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with two equivalent TaO7 pentagonal bipyramids, and edges with two equivalent TaO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There are a spread of Ta–O bond distances ranging from 1.98–2.01 Å. In the second Ta5+ site, Ta5+ is bonded to seven O2- atoms to form distorted TaO7 pentagonal bipyramids that share a cornercorner with one TaO6 octahedra, corners with two equivalent TaO7 pentagonal bipyramids, an edgeedge with one TaO6 octahedra, and edges with two equivalent TaO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There are a spread of Ta–O bond distances ranging from 1.94–2.24 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ho3+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ho3+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to one Ho3+ and two equivalent Ta5+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+ and two Ta5+ atoms.