DOI: 10.17188/1322653
title: Materials Data on CaTa2CoO7 by Materials Project

description: CaTa2CoO7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.79 Å. In the second Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.87 Å. There are four inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share corners with three CoO6 octahedra and a cornercorner with one TaO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 51–67°. There are a spread of Ta–O bond distances ranging from 1.83–1.92 Å. In the second Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 trigonal bipyramids that share corners with two equivalent CoO6 octahedra, a cornercorner with one TaO4 tetrahedra, and an edgeedge with one TaO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 34–51°. There are a spread of Ta–O bond distances ranging from 1.85–2.06 Å. In the third Ta5+ site, Ta5+ is bonded to five O2- atoms to form TaO5 trigonal bipyramids that share corners with three CoO6 octahedra, a cornercorner with one TaO4 tetrahedra, an edgeedge with one CoO6 octahedra, and an edgeedge with one TaO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 42–56°. There are a spread of Ta–O bond distances ranging from 1.84–2.13 Å. In the fourth Ta5+ site, Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share corners with four CoO6 octahedra and a cornercorner with one TaO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 40–61°. There are a spread of Ta–O bond distances ranging from 1.85–1.89 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with three TaO4 tetrahedra, corners with three TaO5 trigonal bipyramids, an edgeedge with one CoO6 octahedra, and an edgeedge with one TaO5 trigonal bipyramid. There are a spread of Co–O bond distances ranging from 2.00–2.52 Å. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four TaO4 tetrahedra, corners with two equivalent TaO5 trigonal bipyramids, and an edgeedge with one CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.04–2.28 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and one Ta5+ atom. In the second O2- site, O2- is bonded in a distorted tetrahedral geometry to two Ca2+, one Ta5+, and one Co2+ atom. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+, one Ta5+, and one Co2+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Ta5+, and one Co2+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Ta5+, and one Co2+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+ and two Co2+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Ta5+, and one Co2+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Ta5+ atoms. In the tenth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two Ta5+ atoms. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+ and two Co2+ atoms. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Ta5+, and one Co2+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ta5+, and one Co2+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Ta5+ and one Co2+ atom.