MgFe2(CoO2)4 crystallizes in the triclinic P1 space group. Mg(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 MgO6 octahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Co(2)O4 tetrahedra,  an edgeedge with one Co(3)O4 tetrahedra,  a faceface with one Co(1)O6 octahedra, and  a faceface with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Co(2)O4 tetrahedra,  an edgeedge with one Co(3)O4 tetrahedra,  a faceface with one Co(1)O6 octahedra, and  a faceface with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-57°. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(3)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-47°. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form distorted CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(3)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Co(4)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-57°. In the second Co site, Co(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Co(1)O6 octahedra, corners with three equivalent Co(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-84°. In the third Co site, Co(3) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Co(1)O6 octahedra, corners with three equivalent Co(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-83°. In the fourth Co site, Co(4) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form distorted CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(3)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Mg(1), one Fe(1), one Fe(2), one Co(1), one Co(3), and one Co(4) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(1), one Co(1), one Co(3), and one Co(4) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Co(3), and one Co(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Fe(1), one Fe(2), one Co(1), and one Co(3) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Co(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Fe(1), one Fe(2), one Co(2), and one Co(4) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(1), one Co(1), one Co(2), and one Co(4) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Mg(1), one Fe(1), one Fe(2), one Co(1), one Co(2), and one Co(4) atom.
MgFe2(CoO2)4 crystallizes in the triclinic P1 space group. Mg(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 MgO6 octahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra,  an edgeedge with one Co(2)O4 tetrahedra,  an edgeedge with one Co(3)O4 tetrahedra,  a faceface with one Co(1)O6 octahedra, and  a faceface with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. The Mg(1)-O(1) bond length is 2.17 Å. The Mg(1)-O(2) bond length is 2.11 Å. The Mg(1)-O(3) bond length is 2.03 Å. The Mg(1)-O(5) bond length is 2.04 Å. The Mg(1)-O(7) bond length is 2.11 Å. The Mg(1)-O(8) bond length is 2.17 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(4), one O(6), one O(7), and one O(8) atom to form FeO6 octahedra that share corners with two equivalent Co(1)O6 octahedra, corners with two equivalent Co(4)O6 octahedra, corners with four equivalent Fe(2)O6 octahedra,  a cornercorner with one Co(2)O4 tetrahedra,  a cornercorner with one Co(3)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Co(2)O4 tetrahedra,  an edgeedge with one Co(3)O4 tetrahedra,  a faceface with one Co(1)O6 octahedra, and  a faceface with one Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-57°. The Fe(1)-O(1) bond length is 2.11 Å. The Fe(1)-O(2) bond length is 2.11 Å. The Fe(1)-O(4) bond length is 2.02 Å. The Fe(1)-O(6) bond length is 2.02 Å. The Fe(1)-O(7) bond length is 2.11 Å. The Fe(1)-O(8) bond length is 2.10 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(8) atom to form FeO6 octahedra that share corners with four equivalent Mg(1)O6 octahedra, corners with four equivalent Fe(1)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(3)O4 tetrahedra, edges with two equivalent Co(1)O6 octahedra, and edges with two equivalent Co(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-47°. The Fe(2)-O(1) bond length is 2.22 Å. The Fe(2)-O(3) bond length is 1.99 Å. The Fe(2)-O(4) bond length is 2.04 Å. The Fe(2)-O(5) bond length is 1.99 Å. The Fe(2)-O(6) bond length is 2.04 Å. The Fe(2)-O(8) bond length is 2.24 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(2), one O(4), one O(5), one O(7), and one O(8) atom to form distorted CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(3)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Co(4)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-57°. The Co(1)-O(1) bond length is 2.36 Å. The Co(1)-O(2) bond length is 2.05 Å. The Co(1)-O(4) bond length is 1.97 Å. The Co(1)-O(5) bond length is 1.94 Å. The Co(1)-O(7) bond length is 2.07 Å. The Co(1)-O(8) bond length is 2.32 Å. In the second Co site, Co(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Co(1)O6 octahedra, corners with three equivalent Co(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-84°. The Co(2)-O(5) bond length is 1.95 Å. The Co(2)-O(6) bond length is 1.99 Å. The Co(2)-O(7) bond length is 1.97 Å. The Co(2)-O(8) bond length is 2.15 Å. In the third Co site, Co(3) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form distorted CoO4 tetrahedra that share  a cornercorner with one Mg(1)O6 octahedra,  a cornercorner with one Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Co(1)O6 octahedra, corners with three equivalent Co(4)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra, and  an edgeedge with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-83°. The Co(3)-O(1) bond length is 2.15 Å. The Co(3)-O(2) bond length is 1.97 Å. The Co(3)-O(3) bond length is 1.95 Å. The Co(3)-O(4) bond length is 1.98 Å. In the fourth Co site, Co(4) is bonded to one O(1), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form distorted CoO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Co(2)O4 tetrahedra, corners with three equivalent Co(3)O4 tetrahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Co(1)O6 octahedra,  a faceface with one Mg(1)O6 octahedra, and  a faceface with one Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. The Co(4)-O(1) bond length is 2.32 Å. The Co(4)-O(2) bond length is 2.07 Å. The Co(4)-O(3) bond length is 1.95 Å. The Co(4)-O(6) bond length is 1.97 Å. The Co(4)-O(7) bond length is 2.05 Å. The Co(4)-O(8) bond length is 2.36 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Mg(1), one Fe(1), one Fe(2), one Co(1), one Co(3), and one Co(4) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(1), one Co(1), one Co(3), and one Co(4) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Co(3), and one Co(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Fe(1), one Fe(2), one Co(1), and one Co(3) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Co(1), and one Co(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one Fe(1), one Fe(2), one Co(2), and one Co(4) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Mg(1), one Fe(1), one Co(1), one Co(2), and one Co(4) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one Mg(1), one Fe(1), one Fe(2), one Co(1), one Co(2), and one Co(4) atom.