CaMn2O4 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Mn(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 0-46°. There are three inequivalent O sites. In the first O site, O(1) 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(3)Ca2Mn4 octahedra, corners with five equivalent O(2)Ca2Mn2 tetrahedra, corners with two equivalent O(1)Ca2Mn3 trigonal bipyramids, edges with three equivalent O(3)Ca2Mn4 octahedra,  an edgeedge with one O(2)Ca2Mn2 tetrahedra, and edges with five equivalent O(1)Ca2Mn3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-43°. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Mn(1) atoms to form distorted OCa2Mn2 tetrahedra that share corners with two equivalent O(2)Ca2Mn2 tetrahedra, corners with ten equivalent O(1)Ca2Mn3 trigonal bipyramids, edges with four equivalent O(3)Ca2Mn4 octahedra, and edges with two equivalent O(1)Ca2Mn3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and four equivalent Mn(1) atoms to form OCa2Mn4 octahedra that share corners with two equivalent O(3)Ca2Mn4 octahedra, corners with eight equivalent O(1)Ca2Mn3 trigonal bipyramids, edges with two equivalent O(3)Ca2Mn4 octahedra, edges with four equivalent O(2)Ca2Mn2 tetrahedra, and edges with six equivalent O(1)Ca2Mn3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°.
CaMn2O4 crystallizes in the orthorhombic Cmcm space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Both Ca(1)-O(2) bond lengths are 2.30 Å. Both Ca(1)-O(3) bond lengths are 2.66 Å. All Ca(1)-O(1) bond lengths are 2.44 Å. Mn(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles range from 0-46°. The Mn(1)-O(2) bond length is 1.93 Å. Both Mn(1)-O(3) bond lengths are 2.20 Å. There is one shorter (1.94 Å) and two longer (2.14 Å) Mn(1)-O(1) bond lengths. There are three inequivalent O sites. In the first O site, O(1) 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(3)Ca2Mn4 octahedra, corners with five equivalent O(2)Ca2Mn2 tetrahedra, corners with two equivalent O(1)Ca2Mn3 trigonal bipyramids, edges with three equivalent O(3)Ca2Mn4 octahedra,  an edgeedge with one O(2)Ca2Mn2 tetrahedra, and edges with five equivalent O(1)Ca2Mn3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-43°. In the second O site, O(2) is bonded to two equivalent Ca(1) and two equivalent Mn(1) atoms to form distorted OCa2Mn2 tetrahedra that share corners with two equivalent O(2)Ca2Mn2 tetrahedra, corners with ten equivalent O(1)Ca2Mn3 trigonal bipyramids, edges with four equivalent O(3)Ca2Mn4 octahedra, and edges with two equivalent O(1)Ca2Mn3 trigonal bipyramids. In the third O site, O(3) is bonded to two equivalent Ca(1) and four equivalent Mn(1) atoms to form OCa2Mn4 octahedra that share corners with two equivalent O(3)Ca2Mn4 octahedra, corners with eight equivalent O(1)Ca2Mn3 trigonal bipyramids, edges with two equivalent O(3)Ca2Mn4 octahedra, edges with four equivalent O(2)Ca2Mn2 tetrahedra, and edges with six equivalent O(1)Ca2Mn3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°.