MgCo6(O5F)2 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form MgO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra and edges with four equivalent Co(4)O6 octahedra. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with eight equivalent Co(3)O5F octahedra and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(2), and two equivalent F(1) atoms. In the third Co site, Co(3) is bonded to one O(1), two equivalent O(3), two equivalent O(4), and one F(1) atom to form CoO5F octahedra that share corners with four equivalent Co(1)O6 octahedra and edges with two equivalent Co(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 50-51°. In the fourth Co site, Co(4) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form CoO6 octahedra that share edges with two equivalent Co(4)O6 octahedra and edges with four equivalent Mg(1)O6 octahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Co(3) and two equivalent Co(1) atoms. In the second O site, O(2) is bonded to two equivalent Mg(1), one Co(4), and two equivalent Co(2) atoms to form a mixture of distorted corner and edge-sharing OMg2Co3 trigonal bipyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(2) and two equivalent Co(3) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Co(1) and two equivalent Co(3) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Co(4) atoms. F(1) is bonded in a 3-coordinate geometry to one Co(3) and two equivalent Co(2) atoms.
MgCo6(O5F)2 crystallizes in the monoclinic P2 space group. Mg(1) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form MgO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra and edges with four equivalent Co(4)O6 octahedra. Both Mg(1)-O(5) bond lengths are 1.96 Å. All Mg(1)-O(2) bond lengths are 2.10 Å. There are four inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(4) and four equivalent O(1) atoms to form CoO6 octahedra that share corners with eight equivalent Co(3)O5F octahedra and edges with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. Both Co(1)-O(4) bond lengths are 1.95 Å. All Co(1)-O(1) bond lengths are 1.87 Å. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(2), and two equivalent F(1) atoms. The Co(2)-O(3) bond length is 1.80 Å. Both Co(2)-O(2) bond lengths are 2.06 Å. There is one shorter (1.99 Å) and one longer (2.00 Å) Co(2)-F(1) bond length. In the third Co site, Co(3) is bonded to one O(1), two equivalent O(3), two equivalent O(4), and one F(1) atom to form CoO5F octahedra that share corners with four equivalent Co(1)O6 octahedra and edges with two equivalent Co(3)O5F octahedra. The corner-sharing octahedral tilt angles range from 50-51°. The Co(3)-O(1) bond length is 2.06 Å. Both Co(3)-O(3) bond lengths are 1.93 Å. Both Co(3)-O(4) bond lengths are 1.87 Å. The Co(3)-F(1) bond length is 2.32 Å. In the fourth Co site, Co(4) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form CoO6 octahedra that share edges with two equivalent Co(4)O6 octahedra and edges with four equivalent Mg(1)O6 octahedra. Both Co(4)-O(2) bond lengths are 1.94 Å. There are two shorter (1.88 Å) and two longer (1.89 Å) Co(4)-O(5) bond lengths. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Co(3) and two equivalent Co(1) atoms. In the second O site, O(2) is bonded to two equivalent Mg(1), one Co(4), and two equivalent Co(2) atoms to form a mixture of distorted corner and edge-sharing OMg2Co3 trigonal bipyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(2) and two equivalent Co(3) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Co(1) and two equivalent Co(3) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Mg(1) and two equivalent Co(4) atoms. F(1) is bonded in a 3-coordinate geometry to one Co(3) and two equivalent Co(2) atoms.