DOI: 10.17188/1321596
title: Materials Data on Ca(NiO2)2 by Materials Project

description: Ca(NiO2)2 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are six inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 55–75°. There are a spread of Ca–O bond distances ranging from 2.16–2.31 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.26–2.33 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four NiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.22–2.28 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.31 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.30 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five NiO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five NiO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.25–2.27 Å. There are nine inequivalent Ni3+ sites. In the first Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four NiO4 tetrahedra, edges with three CaO6 octahedra, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.86–2.17 Å. In the second Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 49–61°. There are a spread of Ni–O bond distances ranging from 1.87–1.96 Å. In the third Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent NiO4 tetrahedra, edges with two CaO6 octahedra, and edges with four NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.86–1.94 Å. In the fourth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with six NiO4 tetrahedra, edges with two equivalent NiO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.91–2.16 Å. In the fifth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 48–64°. There are a spread of Ni–O bond distances ranging from 1.85–1.92 Å. In the sixth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five NiO4 tetrahedra, edges with three CaO6 octahedra, and edges with three NiO6 octahedra. There are a spread of Ni–O bond distances ranging from 1.92–2.32 Å. In the seventh Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 50–67°. There are a spread of Ni–O bond distances ranging from 1.91–2.07 Å. In the eighth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with six CaO6 octahedra and corners with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 51–69°. There are a spread of Ni–O bond distances ranging from 1.91–2.09 Å. In the ninth Ni3+ site, Ni3+ is bonded to four O2- atoms to form NiO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine NiO6 octahedra. The corner-sharing octahedra tilt angles range from 45–66°. There are a spread of Ni–O bond distances ranging from 1.95–2.19 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Ni3+ atoms to form distorted OCa2Ni2 tetrahedra that share corners with two OCa2Ni2 tetrahedra, corners with three OCaNi3 trigonal pyramids, an edgeedge with one OCa2Ni2 tetrahedra, and an edgeedge with one OCaNi3 trigonal pyramid. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the third O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with three OCa2Ni2 tetrahedra, corners with two equivalent OCaNi3 trigonal pyramids, and edges with two equivalent OCa2Ni2 tetrahedra. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the eighth O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with four equivalent OCa2Ni2 tetrahedra and corners with two equivalent OCaNi3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Ni3+ atoms. In the thirteenth O2- site, O2- is bonded to two Ca2+ and two equivalent Ni3+ atoms to form distorted OCa2Ni2 tetrahedra that share corners with two equivalent OCa2Ni2 tetrahedra and a cornercorner with one OCaNi3 trigonal pyramid. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ni3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms.