Materials Data on MgCuO2 by Materials Project

Abstract

CuOMgO crystallizes in the triclinic P-1 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 four equivalent MgO4 tetrahedra, corners with two equivalent CuO5 trigonal bipyramids, edges with two equivalent MgO5 trigonal bipyramids, and a faceface with one CuO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 2.02–2.10 Å. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO4 tetrahedra, corners with four equivalent MgO5 trigonal bipyramids, corners with four equivalent CuO5 trigonal bipyramids, and an edgeedge with one CuO5 trigonal bipyramid. There is three shorter (1.96 Å) and one longer (1.99 Å) Mg–O bond length. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (1.91 Å) and two longer (2.09 Å) Cu–O bond lengths. In the second Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with four equivalent MgO4 tetrahedra, corners with two equivalent MgO5 trigonal bipyramids, an edgeedge with one MgO4 tetrahedra, edges with two equivalent CuO5 trigonal bipyramids, and a faceface with one MgO5 trigonal bipyramid. There are a spread of Cu–O bond distances ranging from 1.99–2.19 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Mg2+ and three Cu2+ atoms to form distorted OMgCu3 tetrahedra that share corners with two equivalent OMgCu3 tetrahedra, corners with four equivalent OMg3Cu2 trigonal bipyramids, and an edgeedge with one OMg3Cu2 trigonal bipyramid. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two equivalent Cu2+ atoms. In the third O2- site, O2- is bonded to three Mg2+ and two equivalent Cu2+ atoms to form distorted OMg3Cu2 trigonal bipyramids that share corners with four equivalent OMgCu3 tetrahedra, an edgeedge with one OMgCu3 tetrahedra, and edges with two equivalent OMg3Cu2 trigonal bipyramids. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Mg2+ and two equivalent Cu2+ atoms.