MgMn2CoO6 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(3), one O(6), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-26°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(6) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. In the second Mn site, Mn(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles are 26°. Co(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Mn(1) and one Co(1) atom. In the second O site, O(2) is bonded to two equivalent Mg(1), one Mn(2), and two equivalent Co(1) atoms to form OMg2MnCo2 square pyramids that share corners with four equivalent O(4)Mg2MnCo2 square pyramids, corners with three equivalent O(6)MgMn3 trigonal pyramids, edges with two equivalent O(2)Mg2MnCo2 square pyramids, and edges with two equivalent O(4)Mg2MnCo2 square pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), and two equivalent Mn(2) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Mn(1), and two equivalent Co(1) atoms to form OMg2MnCo2 square pyramids that share corners with four equivalent O(2)Mg2MnCo2 square pyramids, edges with two equivalent O(2)Mg2MnCo2 square pyramids, edges with two equivalent O(4)Mg2MnCo2 square pyramids, and edges with two equivalent O(6)MgMn3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Mn(2) and one Co(1) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Mn(2), and two equivalent Mn(1) atoms to form distorted OMgMn3 trigonal pyramids that share corners with three equivalent O(2)Mg2MnCo2 square pyramids, corners with two equivalent O(6)MgMn3 trigonal pyramids, and edges with two equivalent O(4)Mg2MnCo2 square pyramids.
MgMn2CoO6 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(3), one O(6), two equivalent O(2), and two equivalent O(4) atoms to form MgO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-26°. The Mg(1)-O(3) bond length is 2.14 Å. The Mg(1)-O(6) bond length is 2.08 Å. Both Mg(1)-O(2) bond lengths are 2.10 Å. Both Mg(1)-O(4) bond lengths are 2.18 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(6) atoms to form MnO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles are 25°. The Mn(1)-O(3) bond length is 1.96 Å. The Mn(1)-O(4) bond length is 1.97 Å. Both Mn(1)-O(1) bond lengths are 1.93 Å. Both Mn(1)-O(6) bond lengths are 1.95 Å. In the second Mn site, Mn(2) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form distorted MnO6 octahedra that share  a cornercorner with one Mg(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles are 26°. The Mn(2)-O(2) bond length is 2.24 Å. The Mn(2)-O(6) bond length is 2.16 Å. Both Mn(2)-O(3) bond lengths are 2.04 Å. Both Mn(2)-O(5) bond lengths are 1.93 Å. Co(1) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-12°. The Co(1)-O(1) bond length is 1.96 Å. The Co(1)-O(5) bond length is 1.90 Å. Both Co(1)-O(2) bond lengths are 1.97 Å. Both Co(1)-O(4) bond lengths are 1.98 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent Mn(1) and one Co(1) atom. In the second O site, O(2) is bonded to two equivalent Mg(1), one Mn(2), and two equivalent Co(1) atoms to form OMg2MnCo2 square pyramids that share corners with four equivalent O(4)Mg2MnCo2 square pyramids, corners with three equivalent O(6)MgMn3 trigonal pyramids, edges with two equivalent O(2)Mg2MnCo2 square pyramids, and edges with two equivalent O(4)Mg2MnCo2 square pyramids. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), and two equivalent Mn(2) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Mn(1), and two equivalent Co(1) atoms to form OMg2MnCo2 square pyramids that share corners with four equivalent O(2)Mg2MnCo2 square pyramids, edges with two equivalent O(2)Mg2MnCo2 square pyramids, edges with two equivalent O(4)Mg2MnCo2 square pyramids, and edges with two equivalent O(6)MgMn3 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Mn(2) and one Co(1) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Mn(2), and two equivalent Mn(1) atoms to form distorted OMgMn3 trigonal pyramids that share corners with three equivalent O(2)Mg2MnCo2 square pyramids, corners with two equivalent O(6)MgMn3 trigonal pyramids, and edges with two equivalent O(4)Mg2MnCo2 square pyramids.