Materials Data on Ca2TaCuO6 by Materials Project

Abstract

Ca2TaCuO6 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.77 Å. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.65 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four equivalent CuO6 octahedra. The corner-sharing octahedra tilt angles range from 28–31°. There is two shorter (1.97 Å) and four longer (2.00 Å) Ta–O bond length. Cu3+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with two equivalent CuO6 octahedra and corners with four equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 28–32°. There are a spread of Cu–O bond distances ranging from 1.94–2.26 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Ta5+, and one Cu3+ atom. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Ta5+, and one Cu3+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded to two Ca2+ and two equivalent Cu3+ atoms to form corner-sharing OCa2Cu2 tetrahedra.