DOI: 10.17188/1319369
title: Materials Data on Ca(NiO2)2 by Materials Project

description: Ca(NiO2)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 pentagonal pyramids that share corners with six NiO6 octahedra and edges with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–20°. There are a spread of Ca–O bond distances ranging from 2.36–2.39 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 pentagonal pyramids that share corners with six NiO6 octahedra and edges with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–20°. There are a spread of Ca–O bond distances ranging from 2.35–2.39 Å. In the third Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.38 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.38 Å. There are eight inequivalent Ni3+ sites. In the first Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three CaO6 pentagonal pyramids, edges with six NiO6 octahedra, and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of Ni–O bond distances ranging from 1.88–2.13 Å. In the second Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three CaO6 pentagonal pyramids, edges with six NiO6 octahedra, and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of Ni–O bond distances ranging from 1.88–2.11 Å. In the third Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three CaO6 pentagonal pyramids, edges with six NiO6 octahedra, and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of Ni–O bond distances ranging from 1.88–2.13 Å. In the fourth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with three CaO6 pentagonal pyramids, edges with six NiO6 octahedra, and an edgeedge with one CaO6 pentagonal pyramid. There are a spread of Ni–O bond distances ranging from 1.88–2.12 Å. In the fifth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share edges with six NiO6 octahedra and edges with two CaO6 pentagonal pyramids. There are a spread of Ni–O bond distances ranging from 1.90–2.16 Å. In the sixth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share edges with six NiO6 octahedra and edges with two CaO6 pentagonal pyramids. There are a spread of Ni–O bond distances ranging from 1.91–2.16 Å. In the seventh Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share edges with six NiO6 octahedra and edges with two CaO6 pentagonal pyramids. There are a spread of Ni–O bond distances ranging from 1.91–2.13 Å. In the eighth Ni3+ site, Ni3+ is bonded to six O2- atoms to form NiO6 octahedra that share edges with six NiO6 octahedra and edges with two CaO6 pentagonal pyramids. There are a spread of Ni–O bond distances ranging from 1.91–2.14 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the second O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with four OCa2Ni3 trigonal bipyramids, corners with five OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and an edgeedge with one OCaNi3 trigonal pyramid. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Ni3+ atoms. In the fourth O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with four OCa2Ni3 trigonal bipyramids, corners with five OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and an edgeedge with one OCaNi3 trigonal pyramid. In the fifth O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with four OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, and edges with four OCa2Ni3 trigonal bipyramids. In the sixth O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with four OCa2Ni3 trigonal bipyramids, corners with six OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and an edgeedge with one OCaNi3 trigonal pyramid. In the seventh O2- site, O2- is bonded to one Ca2+ and three Ni3+ atoms to form distorted OCaNi3 trigonal pyramids that share corners with four OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, and edges with four OCa2Ni3 trigonal bipyramids. 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 OCa2Ni3 trigonal bipyramids, corners with six OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and an edgeedge with one OCaNi3 trigonal pyramid. In the ninth O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form distorted OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with two OCaNi3 trigonal pyramids. In the tenth O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form distorted OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with four OCaNi3 trigonal pyramids. In the eleventh O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with two OCaNi3 trigonal pyramids. In the twelfth O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with four OCaNi3 trigonal pyramids. In the thirteenth O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form distorted OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with two OCaNi3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form distorted OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with four OCaNi3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with two OCaNi3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to two Ca2+ and three Ni3+ atoms to form OCa2Ni3 trigonal bipyramids that share corners with five OCa2Ni3 trigonal bipyramids, corners with three OCaNi3 trigonal pyramids, edges with four OCa2Ni3 trigonal bipyramids, and edges with four OCaNi3 trigonal pyramids.