Materials Data on CaTaAlO5 by Materials Project

Abstract

CaAlTaO5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.54 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 and corners with four equivalent AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. 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 six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four equivalent AlO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are four shorter (1.99 Å) and two longer (2.02 Å) Ta–O bond lengths. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four TaO6 octahedra. The corner-sharing octahedra tilt angles range from 36–53°. There is two shorter (1.77 Å) and two longer (1.78 Å) Al–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ta5+, and one Al3+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ta5+, and one Al3+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+ and two Ta5+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Ca2+, one Ta5+, and one Al3+ atom to form distorted corner-sharing OCa2TaAl tetrahedra. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ta5+, and one Al3+ atom.