MgMn2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(12), and two equivalent O(3) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(7)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(8)O6 octahedra, corners with three equivalent Mg(5)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-62°. In the second Mg site, Mg(2) is bonded to one O(2), one O(4), and two equivalent O(8) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with three equivalent Mg(3)O6 octahedra, and corners with four equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-61°. In the third Mg site, Mg(3) is bonded to one O(4), one O(9), two equivalent O(5), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with three equivalent Mg(2)O4 tetrahedra, corners with three equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. In the fourth Mg site, Mg(4) is bonded to one O(10), one O(6), and two equivalent O(14) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(7)O6 octahedra, corners with three equivalent Mn(5)O6 octahedra, and corners with four equivalent Mn(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. In the fifth Mg site, Mg(5) is bonded to one O(1), one O(18), two equivalent O(16), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Mn(9)O4 tetrahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one Mn(7)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(8)O6 octahedra. In the sixth Mg site, Mg(6) is bonded to one O(15), one O(17), and two equivalent O(11) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(7)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(8)O6 octahedra, corners with three equivalent Mn(5)O6 octahedra, and corners with four equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-60°. There are nine inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(2)O4 tetrahedra,  a cornercorner with one Mn(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Mg(2)O4 tetrahedra,  a cornercorner with one Mn(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(2)O6 octahedra. In the third Mn site, Mn(3) is bonded to one O(13), one O(6), two equivalent O(11), and two equivalent O(8) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(4)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mg(2)O4 tetrahedra, corners with two equivalent Mg(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, and edges with four equivalent Mn(4)O6 octahedra. In the fourth Mn site, Mn(4) is bonded to one O(11), one O(13), one O(15), one O(4), one O(6), and one O(8) atom to form MnO6 octahedra that share  a cornercorner with one Mg(4)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mg(2)O4 tetrahedra, corners with two equivalent Mg(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. In the fifth Mn site, Mn(5) is bonded to one O(10), one O(15), two equivalent O(11), and two equivalent O(14) atoms to form MnO6 octahedra that share corners with three equivalent Mg(4)O4 tetrahedra, corners with three equivalent Mg(6)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Mn(7)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, and edges with two equivalent Mn(8)O6 octahedra. In the sixth Mn site, Mn(6) is bonded to one O(13), one O(9), and two equivalent O(5) atoms to form MnO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with three equivalent Mg(3)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-65°. In the seventh Mn site, Mn(7) is bonded to one O(12), one O(17), two equivalent O(14), and two equivalent O(16) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Mg(6)O4 tetrahedra, corners with two equivalent Mg(4)O4 tetrahedra, corners with two equivalent Mn(9)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, and edges with four equivalent Mn(8)O6 octahedra. In the eighth Mn site, Mn(8) is bonded to one O(10), one O(12), one O(14), one O(16), one O(17), and one O(18) atom to form MnO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Mg(6)O4 tetrahedra, corners with two equivalent Mg(4)O4 tetrahedra, corners with two equivalent Mn(9)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(7)O6 octahedra, and edges with two equivalent Mn(8)O6 octahedra. In the ninth Mn site, Mn(9) is bonded to one O(18), one O(7), and two equivalent O(16) atoms to form MnO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(7)O6 octahedra, corners with three equivalent Mg(5)O6 octahedra, and corners with four equivalent Mn(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-62°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(5), and two equivalent Mn(2) atoms to form distorted corner-sharing OMg2Mn2 trigonal pyramids. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mn(1), and two equivalent Mn(2) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(5), one Mn(1), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), and two equivalent Mn(4) atoms. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Mn(1), one Mn(2), and one Mn(6) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mn(3), and two equivalent Mn(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Mn(9), and two equivalent Mn(2) atoms. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Mn(3), and one Mn(4) atom. In the ninth O site, O(9) is bonded to one Mg(3), one Mn(6), and two equivalent Mn(2) atoms to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(13)Mn4 trigonal pyramid and corners with two equivalent O(1)Mg2Mn2 trigonal pyramids. In the tenth O site, O(10) is bonded to one Mg(4), one Mn(5), and two equivalent Mn(8) atoms to form a mixture of distorted corner and edge-sharing OMgMn3 trigonal pyramids. In the eleventh O site, O(11) is bonded to one Mg(6), one Mn(3), one Mn(4), and one Mn(5) atom to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(10)MgMn3 trigonal pyramid,  a cornercorner with one O(11)MgMn3 trigonal pyramid,  a cornercorner with one O(15)MgMn3 trigonal pyramid, corners with two equivalent O(14)MgMn3 trigonal pyramids,  an edgeedge with one O(11)MgMn3 trigonal pyramid,  an edgeedge with one O(15)MgMn3 trigonal pyramid, and  an edgeedge with one O(13)Mn4 trigonal pyramid. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(7), and two equivalent Mn(8) atoms. In the thirteenth O site, O(13) is bonded to one Mn(3), one Mn(6), and two equivalent Mn(4) atoms to form a mixture of distorted corner and edge-sharing OMn4 trigonal pyramids. In the fourteenth O site, O(14) is bonded to one Mg(4), one Mn(5), one Mn(7), and one Mn(8) atom to form a mixture of distorted corner and edge-sharing OMgMn3 trigonal pyramids. In the fifteenth O site, O(15) is bonded to one Mg(6), one Mn(5), and two equivalent Mn(4) atoms to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(10)MgMn3 trigonal pyramid, corners with two equivalent O(11)MgMn3 trigonal pyramids, corners with two equivalent O(14)MgMn3 trigonal pyramids,  an edgeedge with one O(13)Mn4 trigonal pyramid, and edges with two equivalent O(11)MgMn3 trigonal pyramids. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Mn(7), one Mn(8), and one Mn(9) atom. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Mn(7), and two equivalent Mn(8) atoms. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Mn(9), and two equivalent Mn(8) atoms.
MgMn2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. There are six inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(12), and two equivalent O(3) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(7)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(8)O6 octahedra, corners with three equivalent Mg(5)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-62°. The Mg(1)-O(1) bond length is 2.06 Å. The Mg(1)-O(12) bond length is 2.03 Å. Both Mg(1)-O(3) bond lengths are 2.00 Å. In the second Mg site, Mg(2) is bonded to one O(2), one O(4), and two equivalent O(8) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with three equivalent Mg(3)O6 octahedra, and corners with four equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-61°. The Mg(2)-O(2) bond length is 2.04 Å. The Mg(2)-O(4) bond length is 2.02 Å. Both Mg(2)-O(8) bond lengths are 1.97 Å. In the third Mg site, Mg(3) is bonded to one O(4), one O(9), two equivalent O(5), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with three equivalent Mg(2)O4 tetrahedra, corners with three equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The Mg(3)-O(4) bond length is 2.14 Å. The Mg(3)-O(9) bond length is 2.16 Å. Both Mg(3)-O(5) bond lengths are 2.11 Å. Both Mg(3)-O(8) bond lengths are 2.05 Å. In the fourth Mg site, Mg(4) is bonded to one O(10), one O(6), and two equivalent O(14) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with two equivalent Mn(7)O6 octahedra, corners with three equivalent Mn(5)O6 octahedra, and corners with four equivalent Mn(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-59°. The Mg(4)-O(10) bond length is 2.02 Å. The Mg(4)-O(6) bond length is 2.00 Å. Both Mg(4)-O(14) bond lengths are 2.01 Å. In the fifth Mg site, Mg(5) is bonded to one O(1), one O(18), two equivalent O(16), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Mn(9)O4 tetrahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one Mn(7)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Mn(8)O6 octahedra. The Mg(5)-O(1) bond length is 2.16 Å. The Mg(5)-O(18) bond length is 2.15 Å. Both Mg(5)-O(16) bond lengths are 2.06 Å. Both Mg(5)-O(3) bond lengths are 2.09 Å. In the sixth Mg site, Mg(6) is bonded to one O(15), one O(17), and two equivalent O(11) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mn(7)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with two equivalent Mn(8)O6 octahedra, corners with three equivalent Mn(5)O6 octahedra, and corners with four equivalent Mn(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-60°. The Mg(6)-O(15) bond length is 2.01 Å. The Mg(6)-O(17) bond length is 2.02 Å. Both Mg(6)-O(11) bond lengths are 2.00 Å. There are nine inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(7), two equivalent O(3), and two equivalent O(5) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(2)O4 tetrahedra,  a cornercorner with one Mn(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The Mn(1)-O(2) bond length is 2.26 Å. The Mn(1)-O(7) bond length is 2.28 Å. Both Mn(1)-O(3) bond lengths are 1.96 Å. Both Mn(1)-O(5) bond lengths are 2.00 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(9) atom to form MnO6 octahedra that share  a cornercorner with one Mg(2)O4 tetrahedra,  a cornercorner with one Mn(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Mn(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, and edges with two equivalent Mn(2)O6 octahedra. The Mn(2)-O(1) bond length is 1.97 Å. The Mn(2)-O(2) bond length is 2.00 Å. The Mn(2)-O(3) bond length is 2.10 Å. The Mn(2)-O(5) bond length is 2.00 Å. The Mn(2)-O(7) bond length is 2.00 Å. The Mn(2)-O(9) bond length is 1.97 Å. In the third Mn site, Mn(3) is bonded to one O(13), one O(6), two equivalent O(11), and two equivalent O(8) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(4)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mg(2)O4 tetrahedra, corners with two equivalent Mg(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, and edges with four equivalent Mn(4)O6 octahedra. The Mn(3)-O(13) bond length is 2.27 Å. The Mn(3)-O(6) bond length is 2.28 Å. Both Mn(3)-O(11) bond lengths are 1.99 Å. Both Mn(3)-O(8) bond lengths are 1.94 Å. In the fourth Mn site, Mn(4) is bonded to one O(11), one O(13), one O(15), one O(4), one O(6), and one O(8) atom to form MnO6 octahedra that share  a cornercorner with one Mg(4)O4 tetrahedra,  a cornercorner with one Mn(6)O4 tetrahedra, corners with two equivalent Mg(2)O4 tetrahedra, corners with two equivalent Mg(6)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, and edges with two equivalent Mn(4)O6 octahedra. The Mn(4)-O(11) bond length is 2.28 Å. The Mn(4)-O(13) bond length is 1.99 Å. The Mn(4)-O(15) bond length is 1.99 Å. The Mn(4)-O(4) bond length is 1.99 Å. The Mn(4)-O(6) bond length is 1.97 Å. The Mn(4)-O(8) bond length is 2.18 Å. In the fifth Mn site, Mn(5) is bonded to one O(10), one O(15), two equivalent O(11), and two equivalent O(14) atoms to form MnO6 octahedra that share corners with three equivalent Mg(4)O4 tetrahedra, corners with three equivalent Mg(6)O4 tetrahedra,  an edgeedge with one Mn(3)O6 octahedra,  an edgeedge with one Mn(7)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, and edges with two equivalent Mn(8)O6 octahedra. The Mn(5)-O(10) bond length is 2.26 Å. The Mn(5)-O(15) bond length is 2.23 Å. Both Mn(5)-O(11) bond lengths are 1.97 Å. Both Mn(5)-O(14) bond lengths are 1.99 Å. In the sixth Mn site, Mn(6) is bonded to one O(13), one O(9), and two equivalent O(5) atoms to form MnO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(4)O6 octahedra, corners with three equivalent Mg(3)O6 octahedra, and corners with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 53-65°. The Mn(6)-O(13) bond length is 2.05 Å. The Mn(6)-O(9) bond length is 2.09 Å. Both Mn(6)-O(5) bond lengths are 2.07 Å. In the seventh Mn site, Mn(7) is bonded to one O(12), one O(17), two equivalent O(14), and two equivalent O(16) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Mg(6)O4 tetrahedra, corners with two equivalent Mg(4)O4 tetrahedra, corners with two equivalent Mn(9)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, and edges with four equivalent Mn(8)O6 octahedra. The Mn(7)-O(12) bond length is 2.31 Å. The Mn(7)-O(17) bond length is 2.27 Å. Both Mn(7)-O(14) bond lengths are 1.98 Å. Both Mn(7)-O(16) bond lengths are 1.95 Å. In the eighth Mn site, Mn(8) is bonded to one O(10), one O(12), one O(14), one O(16), one O(17), and one O(18) atom to form MnO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Mg(6)O4 tetrahedra, corners with two equivalent Mg(4)O4 tetrahedra, corners with two equivalent Mn(9)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mn(5)O6 octahedra, edges with two equivalent Mn(7)O6 octahedra, and edges with two equivalent Mn(8)O6 octahedra. The Mn(8)-O(10) bond length is 1.97 Å. The Mn(8)-O(12) bond length is 1.99 Å. The Mn(8)-O(14) bond length is 2.24 Å. The Mn(8)-O(16) bond length is 2.16 Å. The Mn(8)-O(17) bond length is 1.99 Å. The Mn(8)-O(18) bond length is 1.99 Å. In the ninth Mn site, Mn(9) is bonded to one O(18), one O(7), and two equivalent O(16) atoms to form MnO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent Mn(7)O6 octahedra, corners with three equivalent Mg(5)O6 octahedra, and corners with four equivalent Mn(8)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-62°. The Mn(9)-O(18) bond length is 2.06 Å. The Mn(9)-O(7) bond length is 2.04 Å. Both Mn(9)-O(16) bond lengths are 1.99 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mg(5), and two equivalent Mn(2) atoms to form distorted corner-sharing OMg2Mn2 trigonal pyramids. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mn(1), and two equivalent Mn(2) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(5), one Mn(1), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), and two equivalent Mn(4) atoms. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Mn(1), one Mn(2), and one Mn(6) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mn(3), and two equivalent Mn(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Mn(9), and two equivalent Mn(2) atoms. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Mn(3), and one Mn(4) atom. In the ninth O site, O(9) is bonded to one Mg(3), one Mn(6), and two equivalent Mn(2) atoms to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(13)Mn4 trigonal pyramid and corners with two equivalent O(1)Mg2Mn2 trigonal pyramids. In the tenth O site, O(10) is bonded to one Mg(4), one Mn(5), and two equivalent Mn(8) atoms to form a mixture of distorted corner and edge-sharing OMgMn3 trigonal pyramids. In the eleventh O site, O(11) is bonded to one Mg(6), one Mn(3), one Mn(4), and one Mn(5) atom to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(10)MgMn3 trigonal pyramid,  a cornercorner with one O(11)MgMn3 trigonal pyramid,  a cornercorner with one O(15)MgMn3 trigonal pyramid, corners with two equivalent O(14)MgMn3 trigonal pyramids,  an edgeedge with one O(11)MgMn3 trigonal pyramid,  an edgeedge with one O(15)MgMn3 trigonal pyramid, and  an edgeedge with one O(13)Mn4 trigonal pyramid. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(7), and two equivalent Mn(8) atoms. In the thirteenth O site, O(13) is bonded to one Mn(3), one Mn(6), and two equivalent Mn(4) atoms to form a mixture of distorted corner and edge-sharing OMn4 trigonal pyramids. In the fourteenth O site, O(14) is bonded to one Mg(4), one Mn(5), one Mn(7), and one Mn(8) atom to form a mixture of distorted corner and edge-sharing OMgMn3 trigonal pyramids. In the fifteenth O site, O(15) is bonded to one Mg(6), one Mn(5), and two equivalent Mn(4) atoms to form distorted OMgMn3 trigonal pyramids that share  a cornercorner with one O(10)MgMn3 trigonal pyramid, corners with two equivalent O(11)MgMn3 trigonal pyramids, corners with two equivalent O(14)MgMn3 trigonal pyramids,  an edgeedge with one O(13)Mn4 trigonal pyramid, and edges with two equivalent O(11)MgMn3 trigonal pyramids. In the sixteenth O site, O(16) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Mn(7), one Mn(8), and one Mn(9) atom. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Mn(7), and two equivalent Mn(8) atoms. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Mn(9), and two equivalent Mn(8) atoms.