Materials Data on Ca3(CuO3)2 by Materials Project

Abstract

Ca3Cu2O6 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first 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 2.29–2.57 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 2.21–2.61 Å. In the third Ca2+ site, Ca2+ is bonded to seven O2- atoms to form distorted edge-sharing CaO7 hexagonal pyramids. There are a spread of Ca–O bond distances ranging from 2.36–2.50 Å. There are two inequivalent Cu3+ sites. In the first Cu3+ site, Cu3+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.82–1.95 Å. In the second Cu3+ site, Cu3+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.82–1.89 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to three Ca2+ and two equivalent Cu3+ atoms to form distorted OCa3Cu2 trigonal bipyramids that share a cornercorner with one OCa5Cu octahedra, corners with four equivalent OCa4Cu square pyramids, corners with three OCa3Cu2 trigonal bipyramids, an edgeedge with one OCa3Cu2 trigonal bipyramid, and faces with two equivalent OCa5Cu octahedra. The corner-sharing octahedral tilt angles are 39°. In the second O2- site, O2- is bonded to three Ca2+ and two equivalent Cu3+ atoms to form distorted OCa3Cu2 trigonal bipyramids that share corners with five equivalent OCa5Cu octahedra, corners with three OCa3Cu2 trigonal bipyramids, an edgeedge with one OCa3Cu2 trigonal bipyramid, and faces with two equivalent OCa4Cu square pyramids. The corner-sharing octahedra tilt angles range from 39–64°. In the third O2- site, O2- is bonded to four Ca2+ and one Cu3+ atom to form distorted OCa4Cu square pyramids that share corners with four equivalent OCa5Cu octahedra, corners with four equivalent OCa3Cu2 trigonal bipyramids, edges with two equivalent OCa5Cu octahedra, edges with two equivalent OCa4Cu square pyramids, and faces with two equivalent OCa3Cu2 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 5–6°. In the fourth O2- site, O2- is bonded to five Ca2+ and one Cu3+ atom to form distorted OCa5Cu octahedra that share corners with four equivalent OCa4Cu square pyramids, corners with six OCa3Cu2 trigonal bipyramids, edges with two equivalent OCa5Cu octahedra, edges with two equivalent OCa4Cu square pyramids, and faces with two equivalent OCa3Cu2 trigonal bipyramids. In the fifth O2- site, O2- is bonded in a distorted see-saw-like geometry to three Ca2+ and one Cu3+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Ca2+ and one Cu3+ atom.