CaMn2O4 crystallizes in the orthorhombic Pbcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. Mn(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of distorted edge and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 13-44°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and four equivalent Mn(1) atoms to form distorted OCa2Mn4 octahedra that share corners with two equivalent O(1)Ca2Mn4 octahedra, corners with eight equivalent O(3)Ca2Mn3 trigonal bipyramids, edges with two equivalent O(1)Ca2Mn4 octahedra, edges with six equivalent O(3)Ca2Mn3 trigonal bipyramids, and edges with four equivalent O(2)Ca2Mn2 trigonal pyramids. The corner-sharing octahedral tilt angles are 47°. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Mn(1) atoms to form distorted OCa2Mn2 trigonal pyramids that share corners with ten equivalent O(3)Ca2Mn3 trigonal bipyramids, corners with two equivalent O(2)Ca2Mn2 trigonal pyramids, edges with four equivalent O(1)Ca2Mn4 octahedra, and edges with two equivalent O(3)Ca2Mn3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and three equivalent Mn(1) atoms to form distorted OCa2Mn3 trigonal bipyramids that share corners with four equivalent O(1)Ca2Mn4 octahedra, corners with two equivalent O(3)Ca2Mn3 trigonal bipyramids, corners with five equivalent O(2)Ca2Mn2 trigonal pyramids, edges with three equivalent O(1)Ca2Mn4 octahedra, edges with five equivalent O(3)Ca2Mn3 trigonal bipyramids, and  an edgeedge with one O(2)Ca2Mn2 trigonal pyramid. The corner-sharing octahedral tilt angles range from 7-49°.
CaMn2O4 crystallizes in the orthorhombic Pbcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. Both Ca(1)-O(1) bond lengths are 2.64 Å. There is one shorter (2.29 Å) and one longer (2.33 Å) Ca(1)-O(2) bond length. There are two shorter (2.38 Å) and two longer (2.46 Å) Ca(1)-O(3) bond lengths. Mn(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form a mixture of distorted edge and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 13-44°. The Mn(1)-O(2) bond length is 1.89 Å. There is one shorter (1.96 Å) and one longer (2.47 Å) Mn(1)-O(1) bond length. There are a spread of Mn(1)-O(3) bond distances ranging from 1.90-2.38 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(1) and four equivalent Mn(1) atoms to form distorted OCa2Mn4 octahedra that share corners with two equivalent O(1)Ca2Mn4 octahedra, corners with eight equivalent O(3)Ca2Mn3 trigonal bipyramids, edges with two equivalent O(1)Ca2Mn4 octahedra, edges with six equivalent O(3)Ca2Mn3 trigonal bipyramids, and edges with four equivalent O(2)Ca2Mn2 trigonal pyramids. The corner-sharing octahedral tilt angles are 47°. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Mn(1) atoms to form distorted OCa2Mn2 trigonal pyramids that share corners with ten equivalent O(3)Ca2Mn3 trigonal bipyramids, corners with two equivalent O(2)Ca2Mn2 trigonal pyramids, edges with four equivalent O(1)Ca2Mn4 octahedra, and edges with two equivalent O(3)Ca2Mn3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and three equivalent Mn(1) atoms to form distorted OCa2Mn3 trigonal bipyramids that share corners with four equivalent O(1)Ca2Mn4 octahedra, corners with two equivalent O(3)Ca2Mn3 trigonal bipyramids, corners with five equivalent O(2)Ca2Mn2 trigonal pyramids, edges with three equivalent O(1)Ca2Mn4 octahedra, edges with five equivalent O(3)Ca2Mn3 trigonal bipyramids, and  an edgeedge with one O(2)Ca2Mn2 trigonal pyramid. The corner-sharing octahedral tilt angles range from 7-49°.