DOI: 10.17188/1290742
title: Materials Data on CaMn2O4 by Materials Project

description: CaMn2O4 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with four equivalent CaO6 octahedra, corners with six MnO5 square pyramids, and edges with four MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 46–48°. There are a spread of Ca–O bond distances ranging from 2.31–2.45 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with four equivalent CaO6 octahedra, corners with six MnO5 square pyramids, and edges with four MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 47–49°. There are a spread of Ca–O bond distances ranging from 2.31–2.42 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with four CaO6 octahedra, corners with six MnO5 square pyramids, and edges with four MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 46–49°. There are a spread of Ca–O bond distances ranging from 2.29–2.39 Å. There are four inequivalent Mn3+ sites. In the first Mn3+ site, Mn3+ is bonded to five O2- atoms to form distorted MnO5 square pyramids that share corners with three CaO6 octahedra, corners with four MnO5 square pyramids, edges with two CaO6 octahedra, and edges with two equivalent MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 59–71°. There are a spread of Mn–O bond distances ranging from 1.95–2.26 Å. In the second Mn3+ site, Mn3+ is bonded to five O2- atoms to form distorted MnO5 square pyramids that share corners with three CaO6 octahedra, corners with four MnO5 square pyramids, edges with two CaO6 octahedra, and edges with two equivalent MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 59–76°. There are a spread of Mn–O bond distances ranging from 1.94–2.32 Å. In the third Mn3+ site, Mn3+ is bonded to five O2- atoms to form distorted MnO5 square pyramids that share corners with three CaO6 octahedra, corners with four MnO5 square pyramids, edges with two CaO6 octahedra, and edges with two equivalent MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 57–71°. There are a spread of Mn–O bond distances ranging from 1.91–2.34 Å. In the fourth Mn3+ site, Mn3+ is bonded to five O2- atoms to form distorted MnO5 square pyramids that share corners with three CaO6 octahedra, corners with four MnO5 square pyramids, edges with two CaO6 octahedra, and edges with two equivalent MnO5 square pyramids. The corner-sharing octahedra tilt angles range from 56–69°. There are a spread of Mn–O bond distances ranging from 1.91–2.36 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ca2+ and two Mn3+ atoms to form OCa2Mn2 trigonal pyramids that share corners with twelve OCa2Mn2 trigonal pyramids and edges with three OCaMn3 trigonal pyramids. In the second O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form a mixture of distorted corner and edge-sharing OCaMn3 trigonal pyramids. In the third O2- site, O2- is bonded to two Ca2+ and two Mn3+ atoms to form a mixture of corner and edge-sharing OCa2Mn2 trigonal pyramids. In the fourth O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form distorted OCaMn3 trigonal pyramids that share corners with eleven OCa2Mn2 trigonal pyramids and edges with three OCaMn3 trigonal pyramids. In the fifth O2- site, O2- is bonded to two Ca2+ and two equivalent Mn3+ atoms to form OCa2Mn2 trigonal pyramids that share corners with twelve OCa2Mn2 trigonal pyramids and edges with three OCaMn3 trigonal pyramids. In the sixth O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form a mixture of distorted corner and edge-sharing OCaMn3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Ca2+ and three Mn3+ atoms to form a mixture of distorted corner and edge-sharing OCaMn3 trigonal pyramids. In the eighth O2- site, O2- is bonded to two Ca2+ and two equivalent Mn3+ atoms to form OCa2Mn2 trigonal pyramids that share corners with twelve OCa2Mn2 trigonal pyramids and edges with three OCaMn3 trigonal pyramids.