MgMn6O12 crystallizes in the monoclinic Cc space group. Mg(1) is bonded to one O(11), one O(12), one O(3), one O(7), one O(8), and one O(9) atom to form distorted MgO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one Mn(2)O6 octahedra,  a faceface with one Mn(3)O6 octahedra, and  a faceface with one Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted MnO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-58°. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MnO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-58°. In the third Mn site, Mn(3) is bonded to one O(10), one O(11), one O(12), one O(3), one O(7), and one O(8) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra,  an edgeedge with one Mn(6)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-58°. In the fourth Mn site, Mn(4) is bonded to one O(11), one O(12), one O(4), one O(7), one O(8), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra,  an edgeedge with one Mn(6)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. In the fifth Mn site, Mn(5) is bonded to one O(1), one O(10), one O(12), one O(5), one O(6), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Mn(4)O6 octahedra, and edges with two equivalent Mn(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. In the sixth Mn site, Mn(6) is bonded to one O(10), one O(11), one O(2), one O(5), one O(6), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Mn(4)O6 octahedra, and edges with two equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-52°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Mn(5) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Mn(6) atom. In the third O site, O(3) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form a mixture of distorted corner and edge-sharing OMgMn3 tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Mn(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(5), and one Mn(6) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mn(2), one Mn(5), and one Mn(6) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Mg(1), one Mn(2), one Mn(3), and one Mn(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Mg(1), one Mn(1), one Mn(3), and one Mn(4) atom. In the ninth O site, O(9) is bonded to one Mg(1), one Mn(4), one Mn(5), and one Mn(6) atom to form a mixture of corner and edge-sharing OMgMn3 trigonal pyramids. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Mn(3), one Mn(5), and one Mn(6) atom. In the eleventh O site, O(11) is bonded to one Mg(1), one Mn(3), one Mn(4), and one Mn(6) atom to form a mixture of corner and edge-sharing OMgMn3 trigonal pyramids. In the twelfth O site, O(12) is bonded to one Mg(1), one Mn(3), one Mn(4), and one Mn(5) atom to form a mixture of corner and edge-sharing OMgMn3 trigonal pyramids.
MgMn6O12 crystallizes in the monoclinic Cc space group. Mg(1) is bonded to one O(11), one O(12), one O(3), one O(7), one O(8), and one O(9) atom to form distorted MgO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one Mn(2)O6 octahedra,  a faceface with one Mn(3)O6 octahedra, and  a faceface with one Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-53°. The Mg(1)-O(11) bond length is 2.08 Å. The Mg(1)-O(12) bond length is 2.08 Å. The Mg(1)-O(3) bond length is 2.09 Å. The Mg(1)-O(7) bond length is 2.19 Å. The Mg(1)-O(8) bond length is 2.19 Å. The Mg(1)-O(9) bond length is 1.98 Å. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted MnO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-58°. The Mn(1)-O(1) bond length is 1.92 Å. The Mn(1)-O(2) bond length is 1.92 Å. The Mn(1)-O(3) bond length is 1.99 Å. The Mn(1)-O(4) bond length is 1.93 Å. The Mn(1)-O(5) bond length is 2.15 Å. The Mn(1)-O(8) bond length is 2.55 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MnO6 octahedra that share corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(5)O6 octahedra, corners with two equivalent Mn(6)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and edges with two equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-58°. The Mn(2)-O(1) bond length is 1.93 Å. The Mn(2)-O(2) bond length is 1.91 Å. The Mn(2)-O(3) bond length is 1.98 Å. The Mn(2)-O(4) bond length is 1.94 Å. The Mn(2)-O(6) bond length is 2.19 Å. The Mn(2)-O(7) bond length is 2.50 Å. In the third Mn site, Mn(3) is bonded to one O(10), one O(11), one O(12), one O(3), one O(7), and one O(8) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra,  an edgeedge with one Mn(6)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-58°. The Mn(3)-O(10) bond length is 1.90 Å. The Mn(3)-O(11) bond length is 2.01 Å. The Mn(3)-O(12) bond length is 2.00 Å. The Mn(3)-O(3) bond length is 2.05 Å. The Mn(3)-O(7) bond length is 1.91 Å. The Mn(3)-O(8) bond length is 1.91 Å. In the fourth Mn site, Mn(4) is bonded to one O(11), one O(12), one O(4), one O(7), one O(8), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra,  an edgeedge with one Mn(6)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. The Mn(4)-O(11) bond length is 1.98 Å. The Mn(4)-O(12) bond length is 1.98 Å. The Mn(4)-O(4) bond length is 1.87 Å. The Mn(4)-O(7) bond length is 1.93 Å. The Mn(4)-O(8) bond length is 1.93 Å. The Mn(4)-O(9) bond length is 2.00 Å. In the fifth Mn site, Mn(5) is bonded to one O(1), one O(10), one O(12), one O(5), one O(6), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Mn(4)O6 octahedra, and edges with two equivalent Mn(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. The Mn(5)-O(1) bond length is 1.91 Å. The Mn(5)-O(10) bond length is 1.98 Å. The Mn(5)-O(12) bond length is 2.01 Å. The Mn(5)-O(5) bond length is 1.91 Å. The Mn(5)-O(6) bond length is 1.89 Å. The Mn(5)-O(9) bond length is 1.97 Å. In the sixth Mn site, Mn(6) is bonded to one O(10), one O(11), one O(2), one O(5), one O(6), and one O(9) atom to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Mn(4)O6 octahedra, and edges with two equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-52°. The Mn(6)-O(10) bond length is 1.98 Å. The Mn(6)-O(11) bond length is 2.01 Å. The Mn(6)-O(2) bond length is 1.92 Å. The Mn(6)-O(5) bond length is 1.91 Å. The Mn(6)-O(6) bond length is 1.89 Å. The Mn(6)-O(9) bond length is 1.97 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Mn(5) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Mn(6) atom. In the third O site, O(3) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form a mixture of distorted corner and edge-sharing OMgMn3 tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(2), and one Mn(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(5), and one Mn(6) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mn(2), one Mn(5), and one Mn(6) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Mg(1), one Mn(2), one Mn(3), and one Mn(4) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Mg(1), one Mn(1), one Mn(3), and one Mn(4) atom. In the ninth O site, O(9) is bonded to one Mg(1), one Mn(4), one Mn(5), and one Mn(6) atom to form a mixture of corner and edge-sharing OMgMn3 trigonal pyramids. In the tenth O site, O(10) is bonded in a distorted trigonal non-coplanar geometry to one Mn(3), one Mn(5), and one Mn(6) atom. In the eleventh O site, O(11) is bonded to one Mg(1), one Mn(3), one Mn(4), and one Mn(6) atom to form a mixture of corner and edge-sharing OMgMn3 trigonal pyramids. In the twelfth O site, O(12) is bonded to one Mg(1), one Mn(3), one Mn(4), and one Mn(5) atom to form a mixture of corner and edge-sharing OMgMn3 trigonal pyramids.