MgCo6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(5), one O(6), one F(1), one F(2), and one F(4) atom to form MgO3F3 octahedra that share corners with two equivalent Co(5)O3F3 octahedra, corners with two equivalent Co(6)O3F3 octahedra, edges with two equivalent Co(1)O3F3 octahedra, edges with two equivalent Co(2)O3F3 octahedra, and faces with two equivalent Co(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 35-56°. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(5), one O(6), one F(1), one F(2), and one F(5) atom to form distorted CoO3F3 octahedra that share corners with four equivalent Co(4)O3F3 octahedra, corners with four equivalent Co(5)O3F3 octahedra,  an edgeedge with one Co(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and  an edgeedge with one Co(3)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 40-56°. In the second Co site, Co(2) is bonded to one O(2), one O(3), one O(6), one F(1), one F(4), and one F(6) atom to form distorted CoO3F3 octahedra that share corners with four equivalent Co(4)O3F3 octahedra, corners with four equivalent Co(6)O3F3 octahedra,  an edgeedge with one Co(1)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and  an edgeedge with one Co(3)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 36-63°. In the third Co site, Co(3) is bonded to one O(1), one O(2), one O(4), one F(5), and one F(6) atom to form a mixture of distorted edge and corner-sharing CoO3F2 square pyramids. The corner-sharing octahedral tilt angles range from 41-57°. In the fourth Co site, Co(4) is bonded to one O(3), one O(5), one O(6), one F(1), one F(2), and one F(4) atom to form distorted CoO3F3 octahedra that share corners with four equivalent Co(1)O3F3 octahedra, corners with four equivalent Co(2)O3F3 octahedra,  an edgeedge with one Co(5)O3F3 octahedra,  an edgeedge with one Co(6)O3F3 octahedra, and faces with two equivalent Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 36-58°. In the fifth Co site, Co(5) is bonded to one O(1), one O(4), one O(5), one F(2), one F(3), and one F(5) atom to form CoO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with four equivalent Co(1)O3F3 octahedra, corners with three equivalent Co(3)O3F2 square pyramids,  an edgeedge with one Co(4)O3F3 octahedra, and  an edgeedge with one Co(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 38-56°. In the sixth Co site, Co(6) is bonded to one O(2), one O(3), one O(4), one F(3), one F(4), and one F(6) atom to form CoO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with four equivalent Co(2)O3F3 octahedra, corners with three equivalent Co(3)O3F2 square pyramids,  an edgeedge with one Co(4)O3F3 octahedra, and  an edgeedge with one Co(5)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 35-63°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(1), one Co(3), and one Co(5) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Co(2), one Co(3), and one Co(6) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(2), one Co(4), and one Co(6) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(3), one Co(5), and one Co(6) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Co(1), one Co(4), and one Co(5) atom to form a mixture of distorted edge and corner-sharing OMgCo3 trigonal pyramids. In the sixth O site, O(6) is bonded to one Mg(1), one Co(1), one Co(2), and one Co(4) atom to form a mixture of edge and corner-sharing OMgCo3 trigonal pyramids. There are six inequivalent F sites. In the first F site, F(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Co(4) atom. In the second F site, F(2) is bonded in a 4-coordinate geometry to one Mg(1), one Co(1), one Co(4), and one Co(5) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Co(5) and one Co(6) atom. In the fourth F site, F(4) is bonded in a 4-coordinate geometry to one Mg(1), one Co(2), one Co(4), and one Co(6) atom. In the fifth F site, F(5) is bonded in a 3-coordinate geometry to one Co(1), one Co(3), and one Co(5) atom. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Co(2), one Co(3), and one Co(6) atom.
MgCo6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(3), one O(5), one O(6), one F(1), one F(2), and one F(4) atom to form MgO3F3 octahedra that share corners with two equivalent Co(5)O3F3 octahedra, corners with two equivalent Co(6)O3F3 octahedra, edges with two equivalent Co(1)O3F3 octahedra, edges with two equivalent Co(2)O3F3 octahedra, and faces with two equivalent Co(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 35-56°. The Mg(1)-O(3) bond length is 2.08 Å. The Mg(1)-O(5) bond length is 2.10 Å. The Mg(1)-O(6) bond length is 1.99 Å. The Mg(1)-F(1) bond length is 1.92 Å. The Mg(1)-F(2) bond length is 2.05 Å. The Mg(1)-F(4) bond length is 2.03 Å. There are six inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(5), one O(6), one F(1), one F(2), and one F(5) atom to form distorted CoO3F3 octahedra that share corners with four equivalent Co(4)O3F3 octahedra, corners with four equivalent Co(5)O3F3 octahedra,  an edgeedge with one Co(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and  an edgeedge with one Co(3)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 40-56°. The Co(1)-O(1) bond length is 1.84 Å. The Co(1)-O(5) bond length is 2.02 Å. The Co(1)-O(6) bond length is 1.93 Å. The Co(1)-F(1) bond length is 2.13 Å. The Co(1)-F(2) bond length is 2.37 Å. The Co(1)-F(5) bond length is 2.00 Å. In the second Co site, Co(2) is bonded to one O(2), one O(3), one O(6), one F(1), one F(4), and one F(6) atom to form distorted CoO3F3 octahedra that share corners with four equivalent Co(4)O3F3 octahedra, corners with four equivalent Co(6)O3F3 octahedra,  an edgeedge with one Co(1)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and  an edgeedge with one Co(3)O3F2 square pyramid. The corner-sharing octahedral tilt angles range from 36-63°. The Co(2)-O(2) bond length is 1.85 Å. The Co(2)-O(3) bond length is 1.95 Å. The Co(2)-O(6) bond length is 1.92 Å. The Co(2)-F(1) bond length is 2.22 Å. The Co(2)-F(4) bond length is 2.35 Å. The Co(2)-F(6) bond length is 2.02 Å. In the third Co site, Co(3) is bonded to one O(1), one O(2), one O(4), one F(5), and one F(6) atom to form a mixture of distorted edge and corner-sharing CoO3F2 square pyramids. The corner-sharing octahedral tilt angles range from 41-57°. The Co(3)-O(1) bond length is 1.93 Å. The Co(3)-O(2) bond length is 1.89 Å. The Co(3)-O(4) bond length is 1.86 Å. The Co(3)-F(5) bond length is 2.06 Å. The Co(3)-F(6) bond length is 2.11 Å. In the fourth Co site, Co(4) is bonded to one O(3), one O(5), one O(6), one F(1), one F(2), and one F(4) atom to form distorted CoO3F3 octahedra that share corners with four equivalent Co(1)O3F3 octahedra, corners with four equivalent Co(2)O3F3 octahedra,  an edgeedge with one Co(5)O3F3 octahedra,  an edgeedge with one Co(6)O3F3 octahedra, and faces with two equivalent Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 36-58°. The Co(4)-O(3) bond length is 2.00 Å. The Co(4)-O(5) bond length is 1.98 Å. The Co(4)-O(6) bond length is 1.99 Å. The Co(4)-F(1) bond length is 2.30 Å. The Co(4)-F(2) bond length is 2.10 Å. The Co(4)-F(4) bond length is 2.04 Å. In the fifth Co site, Co(5) is bonded to one O(1), one O(4), one O(5), one F(2), one F(3), and one F(5) atom to form CoO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with four equivalent Co(1)O3F3 octahedra, corners with three equivalent Co(3)O3F2 square pyramids,  an edgeedge with one Co(4)O3F3 octahedra, and  an edgeedge with one Co(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 38-56°. The Co(5)-O(1) bond length is 1.97 Å. The Co(5)-O(4) bond length is 1.84 Å. The Co(5)-O(5) bond length is 1.91 Å. The Co(5)-F(2) bond length is 2.30 Å. The Co(5)-F(3) bond length is 1.96 Å. The Co(5)-F(5) bond length is 2.30 Å. In the sixth Co site, Co(6) is bonded to one O(2), one O(3), one O(4), one F(3), one F(4), and one F(6) atom to form CoO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with four equivalent Co(2)O3F3 octahedra, corners with three equivalent Co(3)O3F2 square pyramids,  an edgeedge with one Co(4)O3F3 octahedra, and  an edgeedge with one Co(5)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 35-63°. The Co(6)-O(2) bond length is 2.05 Å. The Co(6)-O(3) bond length is 2.05 Å. The Co(6)-O(4) bond length is 2.04 Å. The Co(6)-F(3) bond length is 2.07 Å. The Co(6)-F(4) bond length is 2.27 Å. The Co(6)-F(6) bond length is 2.23 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(1), one Co(3), and one Co(5) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Co(2), one Co(3), and one Co(6) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(2), one Co(4), and one Co(6) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(3), one Co(5), and one Co(6) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Co(1), one Co(4), and one Co(5) atom to form a mixture of distorted edge and corner-sharing OMgCo3 trigonal pyramids. In the sixth O site, O(6) is bonded to one Mg(1), one Co(1), one Co(2), and one Co(4) atom to form a mixture of edge and corner-sharing OMgCo3 trigonal pyramids. There are six inequivalent F sites. In the first F site, F(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Co(1), one Co(2), and one Co(4) atom. In the second F site, F(2) is bonded in a 4-coordinate geometry to one Mg(1), one Co(1), one Co(4), and one Co(5) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Co(5) and one Co(6) atom. In the fourth F site, F(4) is bonded in a 4-coordinate geometry to one Mg(1), one Co(2), one Co(4), and one Co(6) atom. In the fifth F site, F(5) is bonded in a 3-coordinate geometry to one Co(1), one Co(3), and one Co(5) atom. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Co(2), one Co(3), and one Co(6) atom.