DOI: 10.17188/1321520
title: Materials Data on CaMn2O4 by Materials Project

description: CaMn2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight 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 MnO6 octahedra. The corner-sharing octahedra tilt angles range from 49–72°. There are a spread of Ca–O bond distances ranging from 2.18–2.26 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with three CaO4 tetrahedra, corners with three MnO4 tetrahedra, and edges with six MnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.26–2.31 Å. In the third Ca2+ site, Ca2+ is bonded to four O2- atoms to form CaO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MnO6 octahedra. The corner-sharing octahedra tilt angles range from 55–70°. There are a spread of Ca–O bond distances ranging from 2.19–2.32 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted CaO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four MnO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five MnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.24–2.33 Å. In the fifth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four equivalent MnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.26–2.31 Å. In the sixth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.25–2.36 Å. In the seventh Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five MnO4 tetrahedra, an edgeedge with one CaO6 octahedra, and edges with five MnO6 octahedra. There are four shorter (2.28 Å) and two longer (2.31 Å) Ca–O bond lengths. In the eighth Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MnO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.25–2.35 Å. There are twelve inequivalent Mn3+ sites. In the first Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with three CaO4 tetrahedra, corners with three MnO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.96–2.31 Å. In the second Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent MnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.93–2.07 Å. In the third Mn3+ site, Mn3+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–65°. There are a spread of Mn–O bond distances ranging from 2.01–2.18 Å. In the fourth Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with two equivalent CaO4 tetrahedra, corners with four MnO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.92–2.12 Å. In the fifth Mn3+ site, Mn3+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MnO6 octahedra. The corner-sharing octahedra tilt angles range from 48–66°. There are a spread of Mn–O bond distances ranging from 2.05–2.12 Å. In the sixth Mn3+ site, Mn3+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MnO6 octahedra. The corner-sharing octahedra tilt angles range from 50–64°. There are a spread of Mn–O bond distances ranging from 1.99–2.11 Å. In the seventh Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with six MnO4 tetrahedra, edges with two equivalent MnO6 octahedra, and edges with four CaO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.93–2.09 Å. In the eighth Mn3+ site, Mn3+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MnO6 octahedra. The corner-sharing octahedra tilt angles range from 50–66°. There are a spread of Mn–O bond distances ranging from 2.03–2.19 Å. In the ninth Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share a cornercorner with one CaO4 tetrahedra, corners with five MnO4 tetrahedra, edges with three CaO6 octahedra, and edges with three MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.94–2.31 Å. In the tenth Mn3+ site, Mn3+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with six CaO6 octahedra and corners with six MnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–66°. There are a spread of Mn–O bond distances ranging from 2.02–2.24 Å. In the eleventh Mn3+ site, Mn3+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with three equivalent CaO4 tetrahedra, corners with three equivalent MnO4 tetrahedra, edges with two CaO6 octahedra, and edges with four MnO6 octahedra. There are a spread of Mn–O bond distances ranging from 1.95–2.00 Å. In the twelfth Mn3+ site, Mn3+ is bonded to four O2- atoms to form MnO4 tetrahedra that share corners with three CaO6 octahedra and corners with nine MnO6 octahedra. The corner-sharing octahedra tilt angles range from 44–69°. There are a spread of Mn–O bond distances ranging from 2.11–2.18 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Mn3+ atoms to form distorted OCa2Mn2 tetrahedra that share corners with two OCa2Mn2 tetrahedra, corners with seven OCaMn3 trigonal pyramids, an edgeedge with one OCa2Mn2 tetrahedra, and an edgeedge with one OCa2Mn2 trigonal pyramid. In the second O2- site, O2- is bonded to two Ca2+ and two equivalent Mn3+ atoms to form distorted OCa2Mn2 trigonal pyramids that share corners with two equivalent OCa2Mn2 tetrahedra, corners with seven OCaMn3 trigonal pyramids, and edges with two equivalent OCa2Mn2 tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Mn3+ atoms. In the fifth O2- site, O2- is bonded to two Ca2+ and two Mn3+ atoms to form distorted OCa2Mn2 tetrahedra that share a cornercorner with one OCa2Mn2 tetrahedra, corners with five OCaMn3 trigonal pyramids, and an edgeedge with one OCa2Mn2 tetrahedra. In the sixth O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form distorted OCaMn3 trigonal pyramids that share corners with five OCa2Mn2 tetrahedra, corners with four OCaMn3 trigonal pyramids, and edges with two OCaMn3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the eighth O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form distorted OCaMn3 trigonal pyramids that share corners with four equivalent OCa2Mn2 tetrahedra, corners with five OCaMn3 trigonal pyramids, and edges with two equivalent OCaMn3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Mn3+ atoms. In the eleventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the twelfth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mn3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the fourteenth O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form distorted OCaMn3 trigonal pyramids that share corners with four equivalent OCa2Mn2 tetrahedra and corners with two equivalent OCaMn3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Ca2+ and two Mn3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Ca2+ and two Mn3+ atoms. In the nineteenth O2- site, O2- is bonded to two Ca2+ and two equivalent Mn3+ atoms to form distorted OCa2Mn2 tetrahedra that share corners with two equivalent OCa2Mn2 tetrahedra and corners with seven OCaMn3 trigonal pyramids. In the twentieth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ca2+ and three Mn3+ atoms. In the twenty-second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Mn3+ atoms. In the twenty-third O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form distorted OCaMn3 trigonal pyramids that share corners with four OCa2Mn2 tetrahedra, corners with two OCaMn3 trigonal pyramids, and edges with two OCaMn3 trigonal pyramids. In the twenty-fourth O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form distorted OCaMn3 trigonal pyramids that share corners with three equivalent OCa2Mn2 tetrahedra and edges with two equivalent OCaMn3 trigonal pyramids.