MgW2(OF)4 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 4-coordinate geometry to four equivalent F(2) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent F(1) atoms to form corner-sharing WO4F2 octahedra. The corner-sharing octahedra are not tilted. In the second W site, W(2) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent F(2) atoms to form corner-sharing WO4F2 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent W(1) atoms. In the second O site, O(2) is bonded in a linear geometry to one W(1) and one W(2) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent W(2) atoms. In the fourth O site, O(4) is bonded in a linear geometry to one W(1) and one W(2) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a single-bond geometry to one W(1) atom. In the second F site, F(2) is bonded in a trigonal planar geometry to two equivalent Mg(1) and one W(2) atom.
MgW2(OF)4 crystallizes in the monoclinic Pm space group. Mg(1) is bonded in a 4-coordinate geometry to four equivalent F(2) atoms. There are two shorter (2.03 Å) and two longer (2.52 Å) Mg(1)-F(2) bond lengths. There are two inequivalent W sites. In the first W site, W(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent F(1) atoms to form corner-sharing WO4F2 octahedra. The corner-sharing octahedra are not tilted. The W(1)-O(2) bond length is 1.89 Å. The W(1)-O(4) bond length is 1.89 Å. There is one shorter (1.92 Å) and one longer (1.94 Å) W(1)-O(1) bond length. Both W(1)-F(1) bond lengths are 1.93 Å. In the second W site, W(2) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent F(2) atoms to form corner-sharing WO4F2 octahedra. The corner-sharing octahedra are not tilted. The W(2)-O(2) bond length is 2.00 Å. The W(2)-O(4) bond length is 2.00 Å. Both W(2)-O(3) bond lengths are 1.93 Å. Both W(2)-F(2) bond lengths are 2.16 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent W(1) atoms. In the second O site, O(2) is bonded in a linear geometry to one W(1) and one W(2) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent W(2) atoms. In the fourth O site, O(4) is bonded in a linear geometry to one W(1) and one W(2) atom. There are two inequivalent F sites. In the first F site, F(1) is bonded in a single-bond geometry to one W(1) atom. In the second F site, F(2) is bonded in a trigonal planar geometry to two equivalent Mg(1) and one W(2) atom.