MgCo2O4 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(13), one O(3), and two equivalent O(1) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Co(6)O6 octahedra, corners with three equivalent Co(3)O6 octahedra, and corners with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-61°. In the second Mg site, Mg(2) is bonded to one O(5), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(7)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. In the third Mg site, Mg(3) is bonded to one O(2), one O(8), two equivalent O(1), and two equivalent O(7) atoms to form MgO6 octahedra that share  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Co(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. In the fourth Mg site, Mg(4) is bonded to one O(11), one O(15), two equivalent O(10), and two equivalent O(12) atoms to form MgO6 octahedra that share corners with three equivalent Co(5)O4 tetrahedra, corners with three equivalent Co(8)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Co(6)O6 octahedra. In the fifth Mg site, Mg(5) is bonded to one O(14), one O(6), two equivalent O(12), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Co(5)O4 tetrahedra,  a cornercorner with one Co(7)O4 tetrahedra, corners with two equivalent Co(2)O4 tetrahedra, corners with two equivalent Co(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, and edges with four equivalent Co(4)O6 octahedra. In the sixth Mg site, Mg(6) is bonded to one O(13), one O(18), two equivalent O(10), and two equivalent O(17) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Co(8)O4 tetrahedra, corners with two equivalent Co(5)O4 tetrahedra, corners with two equivalent Co(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, and edges with four equivalent Co(6)O6 octahedra. There are nine inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Co(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. In the second Co site, Co(2) is bonded to one O(2), one O(9), and two equivalent O(4) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-60°. In the third Co site, Co(3) is bonded to one O(16), one O(3), two equivalent O(1), and two equivalent O(17) atoms to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Co(9)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(6)O6 octahedra. In the fourth Co site, Co(4) is bonded to one O(11), one O(12), one O(14), one O(4), one O(6), and one O(9) atom to form CoO6 octahedra that share  a cornercorner with one Co(5)O4 tetrahedra,  a cornercorner with one Co(7)O4 tetrahedra, corners with two equivalent Co(2)O4 tetrahedra, corners with two equivalent Co(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. In the fifth Co site, Co(5) is bonded to one O(15), one O(6), and two equivalent O(10) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Co(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. In the sixth Co site, Co(6) is bonded to one O(10), one O(13), one O(15), one O(16), one O(17), and one O(18) atom to form CoO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Co(8)O4 tetrahedra, corners with two equivalent Co(5)O4 tetrahedra, corners with two equivalent Co(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, and edges with two equivalent Co(6)O6 octahedra. In the seventh Co site, Co(7) is bonded to one O(14), one O(5), and two equivalent O(7) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. In the eighth Co site, Co(8) is bonded to one O(11), one O(18), and two equivalent O(12) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Co(6)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-60°. In the ninth Co site, Co(9) is bonded to one O(16), one O(8), and two equivalent O(17) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with three equivalent Co(3)O6 octahedra, and corners with four equivalent Co(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(3), one Co(1), and one Co(3) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Co(2), and two equivalent Co(1) atoms. In the third O site, O(3) is bonded to one Mg(1), one Co(3), and two equivalent Co(1) atoms to form distorted OMgCo3 trigonal pyramids that share  a cornercorner with one O(16)Co4 trigonal pyramid and  a cornercorner with one O(13)Mg2Co2 trigonal pyramid. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(5), one Co(2), and one Co(4) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Co(7), and two equivalent Co(1) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Co(5), and two equivalent Co(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Co(1), and one Co(7) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Co(9), and two equivalent Co(1) atoms. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Co(2), and two equivalent Co(4) atoms. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(6), one Co(5), and one Co(6) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Co(8), and two equivalent Co(4) atoms. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(5), one Co(4), and one Co(8) atom. In the thirteenth O site, O(13) is bonded to one Mg(1), one Mg(6), and two equivalent Co(6) atoms to form distorted OMg2Co2 trigonal pyramids that share  a cornercorner with one O(3)MgCo3 trigonal pyramid and corners with two equivalent O(16)Co4 trigonal pyramids. In the fourteenth O site, O(14) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Co(7), and two equivalent Co(4) atoms. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Co(5), and two equivalent Co(6) atoms. In the sixteenth O site, O(16) is bonded to one Co(3), one Co(9), and two equivalent Co(6) atoms to form distorted OCo4 trigonal pyramids that share  a cornercorner with one O(3)MgCo3 trigonal pyramid and corners with two equivalent O(13)Mg2Co2 trigonal pyramids. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Co(3), one Co(6), and one Co(9) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Co(8), and two equivalent Co(6) atoms.
MgCo2O4 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(13), one O(3), and two equivalent O(1) atoms to form MgO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Co(6)O6 octahedra, corners with three equivalent Co(3)O6 octahedra, and corners with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-61°. The Mg(1)-O(13) bond length is 1.96 Å. The Mg(1)-O(3) bond length is 2.05 Å. Both Mg(1)-O(1) bond lengths are 1.94 Å. In the second Mg site, Mg(2) is bonded to one O(5), one O(9), two equivalent O(4), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(7)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The Mg(2)-O(5) bond length is 2.07 Å. The Mg(2)-O(9) bond length is 2.08 Å. Both Mg(2)-O(4) bond lengths are 2.06 Å. Both Mg(2)-O(7) bond lengths are 2.06 Å. In the third Mg site, Mg(3) is bonded to one O(2), one O(8), two equivalent O(1), and two equivalent O(7) atoms to form MgO6 octahedra that share  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Co(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, and edges with four equivalent Co(1)O6 octahedra. The Mg(3)-O(2) bond length is 2.08 Å. The Mg(3)-O(8) bond length is 2.10 Å. Both Mg(3)-O(1) bond lengths are 2.01 Å. Both Mg(3)-O(7) bond lengths are 2.05 Å. In the fourth Mg site, Mg(4) is bonded to one O(11), one O(15), two equivalent O(10), and two equivalent O(12) atoms to form MgO6 octahedra that share corners with three equivalent Co(5)O4 tetrahedra, corners with three equivalent Co(8)O4 tetrahedra,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Co(4)O6 octahedra, and edges with two equivalent Co(6)O6 octahedra. The Mg(4)-O(11) bond length is 2.07 Å. The Mg(4)-O(15) bond length is 2.08 Å. Both Mg(4)-O(10) bond lengths are 2.06 Å. Both Mg(4)-O(12) bond lengths are 2.06 Å. In the fifth Mg site, Mg(5) is bonded to one O(14), one O(6), two equivalent O(12), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Co(5)O4 tetrahedra,  a cornercorner with one Co(7)O4 tetrahedra, corners with two equivalent Co(2)O4 tetrahedra, corners with two equivalent Co(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, and edges with four equivalent Co(4)O6 octahedra. The Mg(5)-O(14) bond length is 2.07 Å. The Mg(5)-O(6) bond length is 2.08 Å. Both Mg(5)-O(12) bond lengths are 2.06 Å. Both Mg(5)-O(4) bond lengths are 2.06 Å. In the sixth Mg site, Mg(6) is bonded to one O(13), one O(18), two equivalent O(10), and two equivalent O(17) atoms to form MgO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Co(8)O4 tetrahedra, corners with two equivalent Co(5)O4 tetrahedra, corners with two equivalent Co(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, and edges with four equivalent Co(6)O6 octahedra. The Mg(6)-O(13) bond length is 2.02 Å. The Mg(6)-O(18) bond length is 2.05 Å. Both Mg(6)-O(10) bond lengths are 2.06 Å. Both Mg(6)-O(17) bond lengths are 2.08 Å. There are nine inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(7), and one O(8) atom to form CoO6 octahedra that share  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(9)O4 tetrahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with two equivalent Co(7)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The Co(1)-O(1) bond length is 1.91 Å. The Co(1)-O(2) bond length is 1.97 Å. The Co(1)-O(3) bond length is 1.96 Å. The Co(1)-O(5) bond length is 1.96 Å. The Co(1)-O(7) bond length is 1.92 Å. The Co(1)-O(8) bond length is 1.94 Å. In the second Co site, Co(2) is bonded to one O(2), one O(9), and two equivalent O(4) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-60°. The Co(2)-O(2) bond length is 1.93 Å. The Co(2)-O(9) bond length is 1.94 Å. Both Co(2)-O(4) bond lengths are 1.83 Å. In the third Co site, Co(3) is bonded to one O(16), one O(3), two equivalent O(1), and two equivalent O(17) atoms to form CoO6 octahedra that share corners with three equivalent Mg(1)O4 tetrahedra, corners with three equivalent Co(9)O4 tetrahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(6)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(6)O6 octahedra. The Co(3)-O(16) bond length is 1.98 Å. The Co(3)-O(3) bond length is 1.93 Å. Both Co(3)-O(1) bond lengths are 1.90 Å. Both Co(3)-O(17) bond lengths are 1.96 Å. In the fourth Co site, Co(4) is bonded to one O(11), one O(12), one O(14), one O(4), one O(6), and one O(9) atom to form CoO6 octahedra that share  a cornercorner with one Co(5)O4 tetrahedra,  a cornercorner with one Co(7)O4 tetrahedra, corners with two equivalent Co(2)O4 tetrahedra, corners with two equivalent Co(8)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The Co(4)-O(11) bond length is 1.94 Å. The Co(4)-O(12) bond length is 1.93 Å. The Co(4)-O(14) bond length is 1.93 Å. The Co(4)-O(4) bond length is 1.92 Å. The Co(4)-O(6) bond length is 2.00 Å. The Co(4)-O(9) bond length is 1.98 Å. In the fifth Co site, Co(5) is bonded to one O(15), one O(6), and two equivalent O(10) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Co(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. The Co(5)-O(15) bond length is 1.93 Å. The Co(5)-O(6) bond length is 1.92 Å. Both Co(5)-O(10) bond lengths are 1.83 Å. In the sixth Co site, Co(6) is bonded to one O(10), one O(13), one O(15), one O(16), one O(17), and one O(18) atom to form CoO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Co(8)O4 tetrahedra, corners with two equivalent Co(5)O4 tetrahedra, corners with two equivalent Co(9)O4 tetrahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Co(3)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, and edges with two equivalent Co(6)O6 octahedra. The Co(6)-O(10) bond length is 1.93 Å. The Co(6)-O(13) bond length is 1.93 Å. The Co(6)-O(15) bond length is 1.98 Å. The Co(6)-O(16) bond length is 1.98 Å. The Co(6)-O(17) bond length is 1.95 Å. The Co(6)-O(18) bond length is 1.96 Å. In the seventh Co site, Co(7) is bonded to one O(14), one O(5), and two equivalent O(7) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and corners with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. The Co(7)-O(14) bond length is 1.94 Å. The Co(7)-O(5) bond length is 1.94 Å. Both Co(7)-O(7) bond lengths are 1.83 Å. In the eighth Co site, Co(8) is bonded to one O(11), one O(18), and two equivalent O(12) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(6)O6 octahedra, corners with two equivalent Mg(5)O6 octahedra, corners with two equivalent Co(6)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with four equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-60°. The Co(8)-O(11) bond length is 1.94 Å. The Co(8)-O(18) bond length is 1.94 Å. Both Co(8)-O(12) bond lengths are 1.83 Å. In the ninth Co site, Co(9) is bonded to one O(16), one O(8), and two equivalent O(17) atoms to form CoO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with two equivalent Mg(6)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, corners with three equivalent Co(3)O6 octahedra, and corners with four equivalent Co(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-62°. The Co(9)-O(16) bond length is 1.97 Å. The Co(9)-O(8) bond length is 1.89 Å. Both Co(9)-O(17) bond lengths are 1.88 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(3), one Co(1), and one Co(3) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Co(2), and two equivalent Co(1) atoms. In the third O site, O(3) is bonded to one Mg(1), one Co(3), and two equivalent Co(1) atoms to form distorted OMgCo3 trigonal pyramids that share  a cornercorner with one O(16)Co4 trigonal pyramid and  a cornercorner with one O(13)Mg2Co2 trigonal pyramid. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(5), one Co(2), and one Co(4) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Co(7), and two equivalent Co(1) atoms. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Co(5), and two equivalent Co(4) atoms. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Mg(3), one Co(1), and one Co(7) atom. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Mg(3), one Co(9), and two equivalent Co(1) atoms. In the ninth O site, O(9) is bonded in a rectangular see-saw-like geometry to one Mg(2), one Co(2), and two equivalent Co(4) atoms. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(6), one Co(5), and one Co(6) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Co(8), and two equivalent Co(4) atoms. In the twelfth O site, O(12) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Mg(5), one Co(4), and one Co(8) atom. In the thirteenth O site, O(13) is bonded to one Mg(1), one Mg(6), and two equivalent Co(6) atoms to form distorted OMg2Co2 trigonal pyramids that share  a cornercorner with one O(3)MgCo3 trigonal pyramid and corners with two equivalent O(16)Co4 trigonal pyramids. In the fourteenth O site, O(14) is bonded in a rectangular see-saw-like geometry to one Mg(5), one Co(7), and two equivalent Co(4) atoms. In the fifteenth O site, O(15) is bonded in a rectangular see-saw-like geometry to one Mg(4), one Co(5), and two equivalent Co(6) atoms. In the sixteenth O site, O(16) is bonded to one Co(3), one Co(9), and two equivalent Co(6) atoms to form distorted OCo4 trigonal pyramids that share  a cornercorner with one O(3)MgCo3 trigonal pyramid and corners with two equivalent O(13)Mg2Co2 trigonal pyramids. In the seventeenth O site, O(17) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Co(3), one Co(6), and one Co(9) atom. In the eighteenth O site, O(18) is bonded in a rectangular see-saw-like geometry to one Mg(6), one Co(8), and two equivalent Co(6) atoms.