DOI: 10.17188/1321996
title: Materials Data on MgTa2CuO7 by Materials Project

description: MgTa2CuO7 crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 trigonal bipyramids that share corners with five TaO5 tetrahedra and an edgeedge with one MgO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 2.01–2.12 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six TaO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 1.99–2.46 Å. There are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to five O2- atoms to form distorted TaO5 tetrahedra that share a cornercorner with one MgO6 octahedra, corners with two TaO5 tetrahedra, and corners with two equivalent MgO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 58°. There are a spread of Ta–O bond distances ranging from 1.82–2.56 Å. In the second Ta5+ site, Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share corners with two TaO4 tetrahedra and corners with three equivalent MgO5 trigonal bipyramids. There are a spread of Ta–O bond distances ranging from 1.85–1.87 Å. In the third Ta5+ site, Ta5+ is bonded to four O2- atoms to form distorted TaO4 tetrahedra that share corners with two equivalent MgO6 octahedra and a cornercorner with one TaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 17–51°. There are a spread of Ta–O bond distances ranging from 1.80–1.91 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.94–1.98 Å. In the second Cu2+ site, Cu2+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There is two shorter (1.92 Å) and two longer (1.95 Å) Cu–O bond length. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Mg2+, one Ta5+, and one Cu2+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ta5+ and one Cu2+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Ta5+ and one Cu2+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Mg2+, one Ta5+, and one Cu2+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ta5+, and one Cu2+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta5+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to one Mg2+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Mg2+ and one Ta5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ta5+, and one Cu2+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Ta5+ atoms.