MgCo6(O2F)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with four equivalent Co(1)O3F3 octahedra, edges with four equivalent Co(3)O5F octahedra, and faces with two equivalent Co(2)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-49°. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(4), one F(1), and two equivalent F(2) atoms to form CoO3F3 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Co(4)O4F2 octahedra, corners with four equivalent Co(3)O5F octahedra,  an edgeedge with one Co(1)O3F3 octahedra, and  an edgeedge with one Co(2)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 43-56°. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent F(1) atoms to form CoO4F2 octahedra that share corners with eight equivalent Co(3)O5F octahedra, edges with two equivalent Co(1)O3F3 octahedra, and faces with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. In the third Co site, Co(3) is bonded to one O(1), one O(3), one O(4), two equivalent O(2), and one F(1) atom to form distorted CoO5F octahedra that share corners with four equivalent Co(1)O3F3 octahedra, corners with four equivalent Co(2)O4F2 octahedra,  an edgeedge with one Co(4)O4F2 octahedra,  an edgeedge with one Co(3)O5F octahedra, and edges with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. In the fourth Co site, Co(4) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent F(2) atoms to form CoO4F2 octahedra that share corners with eight equivalent Co(1)O3F3 octahedra and edges with two equivalent Co(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 46-50°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Co(1), one Co(2), and one Co(3) atom. In the second O site, O(2) is bonded to one Mg(1), one Co(2), and two equivalent Co(3) atoms to form a mixture of edge and corner-sharing OMgCo3 trigonal pyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(3), and one Co(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(3), and one Co(4) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to one Mg(1), one Co(1), one Co(2), and one Co(3) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Co(4) and two equivalent Co(1) atoms.
MgCo6(O2F)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent F(1) atoms to form MgO4F2 octahedra that share corners with four equivalent Co(1)O3F3 octahedra, edges with four equivalent Co(3)O5F octahedra, and faces with two equivalent Co(2)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 44-49°. Both Mg(1)-O(1) bond lengths are 2.06 Å. Both Mg(1)-O(2) bond lengths are 1.97 Å. Both Mg(1)-F(1) bond lengths are 2.03 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(3), one O(4), one F(1), and two equivalent F(2) atoms to form CoO3F3 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Co(4)O4F2 octahedra, corners with four equivalent Co(3)O5F octahedra,  an edgeedge with one Co(1)O3F3 octahedra, and  an edgeedge with one Co(2)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 43-56°. The Co(1)-O(1) bond length is 1.96 Å. The Co(1)-O(3) bond length is 1.93 Å. The Co(1)-O(4) bond length is 1.92 Å. The Co(1)-F(1) bond length is 2.11 Å. There is one shorter (1.96 Å) and one longer (2.09 Å) Co(1)-F(2) bond length. In the second Co site, Co(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent F(1) atoms to form CoO4F2 octahedra that share corners with eight equivalent Co(3)O5F octahedra, edges with two equivalent Co(1)O3F3 octahedra, and faces with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. Both Co(2)-O(1) bond lengths are 1.88 Å. Both Co(2)-O(2) bond lengths are 1.94 Å. Both Co(2)-F(1) bond lengths are 2.10 Å. In the third Co site, Co(3) is bonded to one O(1), one O(3), one O(4), two equivalent O(2), and one F(1) atom to form distorted CoO5F octahedra that share corners with four equivalent Co(1)O3F3 octahedra, corners with four equivalent Co(2)O4F2 octahedra,  an edgeedge with one Co(4)O4F2 octahedra,  an edgeedge with one Co(3)O5F octahedra, and edges with two equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 41-56°. The Co(3)-O(1) bond length is 2.21 Å. The Co(3)-O(3) bond length is 1.87 Å. The Co(3)-O(4) bond length is 1.86 Å. There is one shorter (1.93 Å) and one longer (1.96 Å) Co(3)-O(2) bond length. The Co(3)-F(1) bond length is 2.51 Å. In the fourth Co site, Co(4) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent F(2) atoms to form CoO4F2 octahedra that share corners with eight equivalent Co(1)O3F3 octahedra and edges with two equivalent Co(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 46-50°. Both Co(4)-O(3) bond lengths are 1.89 Å. Both Co(4)-O(4) bond lengths are 1.89 Å. Both Co(4)-F(2) bond lengths are 2.41 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Co(1), one Co(2), and one Co(3) atom. In the second O site, O(2) is bonded to one Mg(1), one Co(2), and two equivalent Co(3) atoms to form a mixture of edge and corner-sharing OMgCo3 trigonal pyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(3), and one Co(4) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(3), and one Co(4) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to one Mg(1), one Co(1), one Co(2), and one Co(3) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Co(4) and two equivalent Co(1) atoms.