MgCo6(O2F)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), one O(8), one F(2), and one F(3) atom to form MgO4F2 octahedra that share corners with two equivalent Co(1)O4F2 octahedra, corners with two equivalent Co(3)O4F2 octahedra, corners with two equivalent Co(5)O4F2 octahedra, and edges with two equivalent Co(4)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(6), one O(7), one O(8), one F(1), and one F(3) atom to form CoO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Co(4)O4F2 octahedra, corners with three equivalent Co(3)O4F2 octahedra, and  an edgeedge with one Co(5)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-57°. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one F(1), and one F(3) atom. In the third Co site, Co(3) is bonded to one O(2), one O(3), one O(4), one O(6), one F(1), and one F(4) atom to form CoO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Co(4)O4F2 octahedra, corners with three equivalent Co(1)O4F2 octahedra, and corners with three equivalent Co(5)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. In the fourth Co site, Co(4) is bonded to one O(3), one O(4), one O(5), one O(7), one F(2), and one F(3) atom to form CoO4F2 octahedra that share corners with two equivalent Co(1)O4F2 octahedra, corners with two equivalent Co(3)O4F2 octahedra, corners with two equivalent Co(5)O4F2 octahedra, and edges with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-59°. In the fifth Co site, Co(5) is bonded to one O(1), one O(2), one O(5), one O(6), one F(2), and one F(4) atom to form CoO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Co(4)O4F2 octahedra, corners with three equivalent Co(3)O4F2 octahedra, and  an edgeedge with one Co(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 42-59°. In the sixth Co site, Co(6) is bonded in a 5-coordinate geometry to one O(3), one O(7), one O(8), one F(2), and one F(4) atom. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(2), and one Co(5) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Co(1), one Co(3), and one Co(5) atom. In the third O site, O(3) is bonded to one Mg(1), one Co(3), one Co(4), and one Co(6) atom to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(4)MgCo3 tetrahedra, corners with two equivalent F(3)MgCo3 trigonal pyramids, corners with three equivalent F(2)MgCo3 trigonal pyramids, and  an edgeedge with one O(4)MgCo3 tetrahedra. In the fourth O site, O(4) is bonded to one Mg(1), one Co(2), one Co(3), and one Co(4) atom to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(3)MgCo3 tetrahedra, corners with two equivalent F(2)MgCo3 trigonal pyramids, corners with three equivalent F(3)MgCo3 trigonal pyramids, and  an edgeedge with one O(3)MgCo3 tetrahedra. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(2), one Co(4), and one Co(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(3), and one Co(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(4), and one Co(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(1), and one Co(6) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Co(1), one Co(2), and one Co(3) atom. In the second F site, F(2) is bonded to one Mg(1), one Co(4), one Co(5), and one Co(6) atom to form distorted FMgCo3 trigonal pyramids that share corners with two equivalent O(4)MgCo3 tetrahedra, corners with three equivalent O(3)MgCo3 tetrahedra, and  an edgeedge with one F(3)MgCo3 trigonal pyramid. In the third F site, F(3) is bonded to one Mg(1), one Co(1), one Co(2), and one Co(4) atom to form distorted FMgCo3 trigonal pyramids that share corners with two equivalent O(3)MgCo3 tetrahedra, corners with three equivalent O(4)MgCo3 tetrahedra, and  an edgeedge with one F(2)MgCo3 trigonal pyramid. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Co(3), one Co(5), and one Co(6) atom.
MgCo6(O2F)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(3), one O(4), one O(8), one F(2), and one F(3) atom to form MgO4F2 octahedra that share corners with two equivalent Co(1)O4F2 octahedra, corners with two equivalent Co(3)O4F2 octahedra, corners with two equivalent Co(5)O4F2 octahedra, and edges with two equivalent Co(4)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-56°. The Mg(1)-O(1) bond length is 2.03 Å. The Mg(1)-O(3) bond length is 2.13 Å. The Mg(1)-O(4) bond length is 2.12 Å. The Mg(1)-O(8) bond length is 2.04 Å. The Mg(1)-F(2) bond length is 2.10 Å. The Mg(1)-F(3) bond length is 2.06 Å. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(6), one O(7), one O(8), one F(1), and one F(3) atom to form CoO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Co(4)O4F2 octahedra, corners with three equivalent Co(3)O4F2 octahedra, and  an edgeedge with one Co(5)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-57°. The Co(1)-O(2) bond length is 2.12 Å. The Co(1)-O(6) bond length is 1.86 Å. The Co(1)-O(7) bond length is 2.18 Å. The Co(1)-O(8) bond length is 1.92 Å. The Co(1)-F(1) bond length is 2.06 Å. The Co(1)-F(3) bond length is 2.08 Å. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(1), one O(4), one O(5), one F(1), and one F(3) atom. The Co(2)-O(1) bond length is 1.77 Å. The Co(2)-O(4) bond length is 1.91 Å. The Co(2)-O(5) bond length is 1.86 Å. The Co(2)-F(1) bond length is 2.02 Å. The Co(2)-F(3) bond length is 2.39 Å. In the third Co site, Co(3) is bonded to one O(2), one O(3), one O(4), one O(6), one F(1), and one F(4) atom to form CoO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Co(4)O4F2 octahedra, corners with three equivalent Co(1)O4F2 octahedra, and corners with three equivalent Co(5)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. The Co(3)-O(2) bond length is 1.87 Å. The Co(3)-O(3) bond length is 2.03 Å. The Co(3)-O(4) bond length is 2.03 Å. The Co(3)-O(6) bond length is 1.89 Å. The Co(3)-F(1) bond length is 2.07 Å. The Co(3)-F(4) bond length is 2.07 Å. In the fourth Co site, Co(4) is bonded to one O(3), one O(4), one O(5), one O(7), one F(2), and one F(3) atom to form CoO4F2 octahedra that share corners with two equivalent Co(1)O4F2 octahedra, corners with two equivalent Co(3)O4F2 octahedra, corners with two equivalent Co(5)O4F2 octahedra, and edges with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-59°. The Co(4)-O(3) bond length is 2.07 Å. The Co(4)-O(4) bond length is 2.07 Å. The Co(4)-O(5) bond length is 1.90 Å. The Co(4)-O(7) bond length is 1.89 Å. The Co(4)-F(2) bond length is 2.19 Å. The Co(4)-F(3) bond length is 2.18 Å. In the fifth Co site, Co(5) is bonded to one O(1), one O(2), one O(5), one O(6), one F(2), and one F(4) atom to form CoO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Co(4)O4F2 octahedra, corners with three equivalent Co(3)O4F2 octahedra, and  an edgeedge with one Co(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 42-59°. The Co(5)-O(1) bond length is 2.03 Å. The Co(5)-O(2) bond length is 1.88 Å. The Co(5)-O(5) bond length is 2.04 Å. The Co(5)-O(6) bond length is 2.20 Å. The Co(5)-F(2) bond length is 2.06 Å. The Co(5)-F(4) bond length is 2.03 Å. In the sixth Co site, Co(6) is bonded in a 5-coordinate geometry to one O(3), one O(7), one O(8), one F(2), and one F(4) atom. The Co(6)-O(3) bond length is 1.90 Å. The Co(6)-O(7) bond length is 1.81 Å. The Co(6)-O(8) bond length is 1.83 Å. The Co(6)-F(2) bond length is 2.36 Å. The Co(6)-F(4) bond length is 2.03 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(2), and one Co(5) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Co(1), one Co(3), and one Co(5) atom. In the third O site, O(3) is bonded to one Mg(1), one Co(3), one Co(4), and one Co(6) atom to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(4)MgCo3 tetrahedra, corners with two equivalent F(3)MgCo3 trigonal pyramids, corners with three equivalent F(2)MgCo3 trigonal pyramids, and  an edgeedge with one O(4)MgCo3 tetrahedra. In the fourth O site, O(4) is bonded to one Mg(1), one Co(2), one Co(3), and one Co(4) atom to form distorted OMgCo3 tetrahedra that share  a cornercorner with one O(3)MgCo3 tetrahedra, corners with two equivalent F(2)MgCo3 trigonal pyramids, corners with three equivalent F(3)MgCo3 trigonal pyramids, and  an edgeedge with one O(3)MgCo3 tetrahedra. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(2), one Co(4), and one Co(5) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(3), and one Co(5) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(4), and one Co(6) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(1), and one Co(6) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Co(1), one Co(2), and one Co(3) atom. In the second F site, F(2) is bonded to one Mg(1), one Co(4), one Co(5), and one Co(6) atom to form distorted FMgCo3 trigonal pyramids that share corners with two equivalent O(4)MgCo3 tetrahedra, corners with three equivalent O(3)MgCo3 tetrahedra, and  an edgeedge with one F(3)MgCo3 trigonal pyramid. In the third F site, F(3) is bonded to one Mg(1), one Co(1), one Co(2), and one Co(4) atom to form distorted FMgCo3 trigonal pyramids that share corners with two equivalent O(3)MgCo3 tetrahedra, corners with three equivalent O(4)MgCo3 tetrahedra, and  an edgeedge with one F(2)MgCo3 trigonal pyramid. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Co(3), one Co(5), and one Co(6) atom.