Ca3MnO4 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CaO6 octahedra that share corners with six equivalent Ca(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra, and edges with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. In the second Ca site, Ca(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form CaO6 octahedra that share corners with three equivalent Ca(1)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, edges with three equivalent Ca(1)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. Mn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with six equivalent Ca(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), three equivalent Ca(2), and two equivalent Mn(1) atoms to form OCa4Mn2 octahedra that share corners with three equivalent O(1)Ca4Mn2 octahedra, corners with three equivalent O(2)Ca5Mn octahedra, edges with five equivalent O(1)Ca4Mn2 octahedra, and edges with seven equivalent O(2)Ca5Mn octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second O site, O(2) is bonded to two equivalent Ca(1), three equivalent Ca(2), and one Mn(1) atom to form OCa5Mn octahedra that share corners with three equivalent O(1)Ca4Mn2 octahedra, corners with three equivalent O(2)Ca5Mn octahedra, edges with five equivalent O(2)Ca5Mn octahedra, and edges with seven equivalent O(1)Ca4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.
Ca3MnO4 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form CaO6 octahedra that share corners with six equivalent Ca(2)O6 octahedra, edges with two equivalent Ca(1)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra, and edges with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. Both Ca(1)-O(1) bond lengths are 2.36 Å. All Ca(1)-O(2) bond lengths are 2.37 Å. In the second Ca site, Ca(2) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form CaO6 octahedra that share corners with three equivalent Ca(1)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, edges with three equivalent Ca(1)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. There is one shorter (2.33 Å) and two longer (2.41 Å) Ca(2)-O(1) bond lengths. There are two shorter (2.34 Å) and one longer (2.42 Å) Ca(2)-O(2) bond length. Mn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with six equivalent Ca(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with four equivalent Ca(1)O6 octahedra, and edges with six equivalent Ca(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. Both Mn(1)-O(2) bond lengths are 2.32 Å. All Mn(1)-O(1) bond lengths are 2.30 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), three equivalent Ca(2), and two equivalent Mn(1) atoms to form OCa4Mn2 octahedra that share corners with three equivalent O(1)Ca4Mn2 octahedra, corners with three equivalent O(2)Ca5Mn octahedra, edges with five equivalent O(1)Ca4Mn2 octahedra, and edges with seven equivalent O(2)Ca5Mn octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second O site, O(2) is bonded to two equivalent Ca(1), three equivalent Ca(2), and one Mn(1) atom to form OCa5Mn octahedra that share corners with three equivalent O(1)Ca4Mn2 octahedra, corners with three equivalent O(2)Ca5Mn octahedra, edges with five equivalent O(2)Ca5Mn octahedra, and edges with seven equivalent O(1)Ca4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-2°.