MgFe4(CoO6)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and faces with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-46°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(11), one O(3), one O(5), and one O(7) atom to form FeO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra, corners with four equivalent Co(2)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. In the second Fe site, Fe(2) is bonded to one O(10), one O(12), one O(2), one O(3), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Fe(4)O6 octahedra, corners with four equivalent Co(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(4), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra, corners with four equivalent Co(1)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. In the fourth Fe site, Fe(4) is bonded to one O(12), one O(2), one O(4), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-55°. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(9) atom to form CoO6 octahedra that share corners with four equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-51°. In the second Co site, Co(2) is bonded to one O(10), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-51°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(1), one Fe(3), and one Co(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(4), and one Co(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Co(2) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Co(1) atom to form a mixture of edge and corner-sharing OMgFe2Co trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Co(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Co(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(2) atom. In the ninth O site, O(9) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Co(1) atom to form a mixture of edge and corner-sharing OMgFe2Co trigonal pyramids. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one Co(2) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(3), and one Co(1) atom. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(4), and one Co(1) atom.
MgFe4(CoO6)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(9) atom to form MgO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and faces with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-46°. The Mg(1)-O(1) bond length is 2.05 Å. The Mg(1)-O(11) bond length is 2.06 Å. The Mg(1)-O(12) bond length is 2.08 Å. The Mg(1)-O(2) bond length is 2.05 Å. The Mg(1)-O(4) bond length is 1.93 Å. The Mg(1)-O(9) bond length is 1.94 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(11), one O(3), one O(5), and one O(7) atom to form FeO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Fe(3)O6 octahedra, corners with four equivalent Co(2)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and  an edgeedge with one Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. The Fe(1)-O(1) bond length is 2.02 Å. The Fe(1)-O(10) bond length is 1.94 Å. The Fe(1)-O(11) bond length is 2.01 Å. The Fe(1)-O(3) bond length is 2.01 Å. The Fe(1)-O(5) bond length is 2.09 Å. The Fe(1)-O(7) bond length is 2.09 Å. In the second Fe site, Fe(2) is bonded to one O(10), one O(12), one O(2), one O(3), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Fe(4)O6 octahedra, corners with four equivalent Co(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, and  an edgeedge with one Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. The Fe(2)-O(10) bond length is 1.89 Å. The Fe(2)-O(12) bond length is 2.02 Å. The Fe(2)-O(2) bond length is 1.99 Å. The Fe(2)-O(3) bond length is 1.99 Å. The Fe(2)-O(6) bond length is 2.10 Å. The Fe(2)-O(8) bond length is 2.08 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(11), one O(4), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra, corners with four equivalent Co(1)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. The Fe(3)-O(1) bond length is 2.30 Å. The Fe(3)-O(11) bond length is 2.05 Å. The Fe(3)-O(4) bond length is 2.01 Å. The Fe(3)-O(5) bond length is 1.92 Å. The Fe(3)-O(7) bond length is 1.93 Å. The Fe(3)-O(9) bond length is 2.02 Å. In the fourth Fe site, Fe(4) is bonded to one O(12), one O(2), one O(4), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with four equivalent Fe(2)O6 octahedra, corners with four equivalent Co(1)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra,  an edgeedge with one Co(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-55°. The Fe(4)-O(12) bond length is 2.19 Å. The Fe(4)-O(2) bond length is 2.15 Å. The Fe(4)-O(4) bond length is 2.00 Å. The Fe(4)-O(6) bond length is 1.91 Å. The Fe(4)-O(8) bond length is 1.91 Å. The Fe(4)-O(9) bond length is 1.99 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(11), one O(12), one O(2), one O(4), and one O(9) atom to form CoO6 octahedra that share corners with four equivalent Fe(3)O6 octahedra, corners with four equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Fe(2)O6 octahedra, and faces with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-51°. The Co(1)-O(1) bond length is 1.86 Å. The Co(1)-O(11) bond length is 1.93 Å. The Co(1)-O(12) bond length is 1.87 Å. The Co(1)-O(2) bond length is 1.94 Å. The Co(1)-O(4) bond length is 2.05 Å. The Co(1)-O(9) bond length is 2.05 Å. In the second Co site, Co(2) is bonded to one O(10), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  an edgeedge with one Fe(3)O6 octahedra, and  an edgeedge with one Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-51°. The Co(2)-O(10) bond length is 2.41 Å. The Co(2)-O(3) bond length is 1.89 Å. The Co(2)-O(5) bond length is 1.86 Å. The Co(2)-O(6) bond length is 1.87 Å. The Co(2)-O(7) bond length is 1.86 Å. The Co(2)-O(8) bond length is 1.87 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Fe(1), one Fe(3), and one Co(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(4), and one Co(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Fe(1), one Fe(2), and one Co(2) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Co(1) atom to form a mixture of edge and corner-sharing OMgFe2Co trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Co(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(3), and one Co(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Co(2) atom. In the ninth O site, O(9) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Co(1) atom to form a mixture of edge and corner-sharing OMgFe2Co trigonal pyramids. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Fe(1), one Fe(2), and one Co(2) atom. In the eleventh O site, O(11) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(1), one Fe(3), and one Co(1) atom. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(4), and one Co(1) atom.