MgMn4O8 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a body-centered cubic geometry to eight O(2,2) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to three O(1,1) and three equivalent O(2) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 53°. In the second Mn site, Mn(1) is bonded to three O(1,1) and three equivalent O(2) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three Mn(1,1) atoms. In the second O site, O(1) is bonded in a trigonal planar geometry to three Mn(1,1) atoms. In the third O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(1) and three equivalent Mn(1) atoms. In the fourth O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(1) and three equivalent Mn(1) atoms.
MgMn4O8 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a body-centered cubic geometry to eight O(2,2) atoms. All Mg(1)-O(2,2) bond lengths are 2.67 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to three O(1,1) and three equivalent O(2) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There is one shorter (1.87 Å) and two longer (1.93 Å) Mn(1)-O(1,1) bond lengths. There is one shorter (2.01 Å) and two longer (2.09 Å) Mn(1)-O(2) bond lengths. In the second Mn site, Mn(1) is bonded to three O(1,1) and three equivalent O(2) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 53°. There is one shorter (1.87 Å) and two longer (1.93 Å) Mn(1)-O(1,1) bond lengths. There is one shorter (2.01 Å) and two longer (2.10 Å) Mn(1)-O(2) bond lengths. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three Mn(1,1) atoms. In the second O site, O(1) is bonded in a trigonal planar geometry to three Mn(1,1) atoms. In the third O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(1) and three equivalent Mn(1) atoms. In the fourth O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Mg(1) and three equivalent Mn(1) atoms.