DOI: 10.17188/1322646
title: Materials Data on Ta2CoO7 by Materials Project

description: Ta2CoO7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. 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 40–62°. There are a spread of Ta–O bond distances ranging from 1.79–1.91 Å. In the second Ta5+ site, Ta5+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ta–O bond distances ranging from 1.76–2.18 Å. In the third Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 trigonal bipyramids that share corners with three CoO6 octahedra, a cornercorner with one TaO4 tetrahedra, and an edgeedge with one CoO6 octahedra. The corner-sharing octahedra tilt angles range from 31–52°. There are a spread of Ta–O bond distances ranging from 1.85–2.07 Å. In the fourth Ta5+ site, Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share corners with four CoO6 octahedra. The corner-sharing octahedra tilt angles range from 43–54°. There are a spread of Ta–O bond distances ranging from 1.82–1.93 Å. There are two inequivalent Co4+ sites. In the first Co4+ site, Co4+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with three TaO4 tetrahedra, a cornercorner with one TaO5 trigonal bipyramid, 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 1.79–2.32 Å. In the second Co4+ site, Co4+ 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 1.84–2.11 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ta5+ and one Co4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Ta5+ and one Co4+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ta5+ and one Co4+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ta5+ and one Co4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ta5+ and one Co4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Ta5+ and one Co4+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+ and two Co4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ta5+ and one Co4+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+ and two Co4+ atoms. In the tenth O2- site, O2- is bonded in a single-bond geometry to one Ta5+ atom. In the eleventh O2- site, O2- is bonded in a bent 120 degrees geometry to two Ta5+ atoms. In the twelfth O2- site, O2- is bonded in a single-bond geometry to one Ta5+ atom. In the thirteenth O2- site, O2- is bonded in a water-like geometry to two Ta5+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ta5+ and one Co4+ atom.