DOI: 10.17188/1321396
title: Materials Data on Ca(CoO2)2 by Materials Project

description: CaCo2O4 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 CoO6 octahedra. The corner-sharing octahedra tilt angles range from 54–73°. There are a spread of Ca–O bond distances ranging from 2.14–2.26 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six CoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.23–2.31 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 CoO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.21–2.27 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six CoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.23–2.30 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six CoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent CoO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.23–2.29 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 CoO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five CoO6 octahedra. There are four shorter (2.24 Å) and two longer (2.25 Å) Ca–O bond lengths. There are nine inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four CoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.89–2.09 Å. In the second Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 49–64°. There are a spread of Co–O bond distances ranging from 1.85–2.02 Å. In the third Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent CoO4 tetrahedra, edges with two CaO6 octahedra, and edges with four CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.85–2.00 Å. In the fourth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO4 tetrahedra, edges with two equivalent CoO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Co–O bond distances ranging from 1.93–2.06 Å. In the fifth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 48–65°. There are a spread of Co–O bond distances ranging from 1.85–1.97 Å. In the sixth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five CoO4 tetrahedra, edges with three CaO6 octahedra, and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.93–2.12 Å. In the seventh Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 48–64°. There are a spread of Co–O bond distances ranging from 1.86–2.00 Å. In the eighth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with six CaO6 octahedra and corners with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 49–63°. There are a spread of Co–O bond distances ranging from 1.86–2.04 Å. In the ninth Co3+ site, Co3+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 53–66°. There are a spread of Co–O bond distances ranging from 1.97–2.30 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Co3+ atoms to form distorted OCa2Co2 trigonal pyramids that share corners with two OCaCo3 tetrahedra, corners with six OCa2Co2 trigonal pyramids, an edgeedge with one OCaCo3 tetrahedra, and an edgeedge with one OCa2Co2 trigonal pyramid. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms. In the third O2- site, O2- is bonded to one Ca2+ and three Co3+ atoms to form a mixture of distorted corner and edge-sharing OCaCo3 tetrahedra. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Co3+ atoms. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Co3+ atoms. In the eighth O2- site, O2- is bonded to one Ca2+ and three Co3+ atoms to form distorted OCaCo3 trigonal pyramids that share corners with two equivalent OCaCo3 tetrahedra and corners with seven OCa2Co2 trigonal pyramids. In the ninth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Co3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Co3+ atoms. In the thirteenth O2- site, O2- is bonded to two Ca2+ and two equivalent Co3+ atoms to form distorted OCa2Co2 tetrahedra that share a cornercorner with one OCaCo3 tetrahedra and corners with eight OCa2Co2 trigonal pyramids. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms. In the sixteenth O2- site, O2- is bonded to four Co3+ atoms to form distorted OCo4 trigonal pyramids that share corners with three OCaCo3 tetrahedra, corners with five OCa2Co2 trigonal pyramids, and edges with two equivalent OCaCo3 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to one Ca2+ and three Co3+ atoms to form distorted OCaCo3 trigonal pyramids that share corners with three OCaCo3 tetrahedra, corners with five OCa2Co2 trigonal pyramids, and edges with two OCo4 trigonal pyramids. In the eighteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Co3+ atoms.