Materials Data on CaNiO2 by Materials Project

Abstract

NiOCaO crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to five O2- atoms to form distorted CaO5 trigonal bipyramids that share corners with four equivalent CaO4 tetrahedra, corners with two equivalent NiO5 trigonal bipyramids, edges with two equivalent CaO5 trigonal bipyramids, and a faceface with one NiO5 trigonal bipyramid. There are a spread of Ca–O bond distances ranging from 2.24–2.38 Å. In the second Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with two equivalent CaO4 tetrahedra, corners with four equivalent CaO5 trigonal bipyramids, corners with four equivalent NiO5 trigonal bipyramids, and an edgeedge with one NiO5 trigonal bipyramid. There are a spread of Ca–O bond distances ranging from 2.17–2.31 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.91 Å) and two longer (2.02 Å) Ni–O bond length. In the second Ni2+ site, Ni2+ is bonded to five O2- atoms to form distorted NiO5 trigonal bipyramids that share corners with four equivalent CaO4 tetrahedra, corners with two equivalent CaO5 trigonal bipyramids, an edgeedge with one CaO4 tetrahedra, edges with two equivalent NiO5 trigonal bipyramids, and a faceface with one CaO5 trigonal bipyramid. There are a spread of Ni–O bond distances ranging from 2.01–2.24 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and three Ni2+ atoms to form distorted OCaNi3 tetrahedra that share corners with two equivalent OCaNi3 tetrahedra, corners with four equivalent OCa3Ni2 trigonal bipyramids, and edges with three OCa3Ni2 trigonal bipyramids. In the second O2- site, O2- is bonded in a square co-planar geometry to two equivalent Ca2+ and two equivalent Ni2+ atoms. In the third O2- site, O2- is bonded to three Ca2+ and two equivalent Ni2+ atoms to form distorted OCa3Ni2 trigonal bipyramids that share corners with four equivalent OCaNi3 tetrahedra, corners with three equivalent OCa3Ni2 trigonal bipyramids, an edgeedge with one OCaNi3 tetrahedra, and edges with three OCa3Ni2 trigonal bipyramids. In the fourth O2- site, O2- is bonded to three Ca2+ and two equivalent Ni2+ atoms to form distorted OCa3Ni2 trigonal bipyramids that share corners with three equivalent OCa3Ni2 trigonal bipyramids, edges with two equivalent OCaNi3 tetrahedra, and edges with three OCa3Ni2 trigonal bipyramids.