Materials Data on TaNbCu3O8 by Materials Project

Abstract

TaNbCu3O8 crystallizes in the triclinic P1 space group. The structure is three-dimensional. Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with five CuO5 square pyramids, edges with two equivalent NbO6 octahedra, and an edgeedge with one CuO5 square pyramid. There are a spread of Ta–O bond distances ranging from 1.88–2.28 Å. Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with five CuO5 square pyramids, edges with two equivalent TaO6 octahedra, and an edgeedge with one CuO5 square pyramid. There are a spread of Nb–O bond distances ranging from 1.88–2.34 Å. There are three inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a distorted square co-planar geometry to four O2- atoms. There is two shorter (1.93 Å) and two longer (1.96 Å) Cu–O bond length. In the second Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 square pyramids that share corners with two equivalent NbO6 octahedra, corners with three equivalent TaO6 octahedra, an edgeedge with one NbO6 octahedra, and an edgeedge with one CuO5 square pyramid. The corner-sharing octahedra tilt angles range from 37–56°. There are a spread of Cu–O bond distances ranging from 1.96–2.32 Å. In the third Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 square pyramids that share corners with two equivalent TaO6 octahedra, corners with three equivalent NbO6 octahedra, an edgeedge with one TaO6 octahedra, and an edgeedge with one CuO5 square pyramid. The corner-sharing octahedra tilt angles range from 39–57°. There are a spread of Cu–O bond distances ranging from 1.95–2.30 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ta5+ and three Cu2+ atoms to form a mixture of distorted edge and corner-sharing OTaCu3 trigonal pyramids. In the second O2- site, O2- is bonded to one Nb5+ and three Cu2+ atoms to form a mixture of distorted edge and corner-sharing ONbCu3 trigonal pyramids. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+ and two Cu2+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Nb5+ and two Cu2+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ta5+, one Nb5+, and one Cu2+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ta5+, one Nb5+, and one Cu2+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ta5+, one Nb5+, and one Cu2+ atom. In the eighth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ta5+, one Nb5+, and one Cu2+ atom.