MgMn2O4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), and two equivalent O(4) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form edge-sharing MnO6 octahedra. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), and two equivalent Mn(2) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Mn(2) and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded to one Mg(1), one Mn(2), and two equivalent Mn(1) atoms to form distorted corner-sharing OMgMn3 trigonal pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Mn(1), and two equivalent Mn(2) atoms.
MgMn2O4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(3), and two equivalent O(4) atoms. The Mg(1)-O(1) bond length is 1.91 Å. The Mg(1)-O(3) bond length is 2.11 Å. There is one shorter (2.00 Å) and one longer (2.02 Å) Mg(1)-O(4) bond length. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form edge-sharing MnO6 octahedra. The Mn(1)-O(1) bond length is 2.34 Å. The Mn(1)-O(4) bond length is 2.30 Å. There is one shorter (1.98 Å) and one longer (2.00 Å) Mn(1)-O(2) bond length. There is one shorter (1.99 Å) and one longer (2.04 Å) Mn(1)-O(3) bond length. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. The Mn(2)-O(2) bond length is 1.93 Å. The Mn(2)-O(3) bond length is 2.06 Å. There is one shorter (1.92 Å) and one longer (2.09 Å) Mn(2)-O(1) bond length. There is one shorter (1.99 Å) and one longer (2.57 Å) Mn(2)-O(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), and two equivalent Mn(2) atoms. In the second O site, O(2) is bonded in a trigonal non-coplanar geometry to one Mn(2) and two equivalent Mn(1) atoms. In the third O site, O(3) is bonded to one Mg(1), one Mn(2), and two equivalent Mn(1) atoms to form distorted corner-sharing OMgMn3 trigonal pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Mn(1), and two equivalent Mn(2) atoms.