MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to two equivalent O(4), two equivalent O(6), one F(1), and one F(4) atom to form distorted MgO4F2 octahedra that share corners with two equivalent Fe(4)O4F2 octahedra, corners with two equivalent Fe(5)O3F tetrahedra, edges with two equivalent Mg(1)O4F2 octahedra, edges with four equivalent Fe(2)O2F4 octahedra, and  a faceface with one Fe(4)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-38°. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(1), one F(3), and two equivalent F(6) atoms to form FeO3F3 octahedra that share corners with four equivalent Fe(6)O3F3 octahedra, corners with four equivalent Fe(4)O4F2 octahedra, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. In the second Fe site, Fe(2) is bonded to one O(4), one O(6), two equivalent F(1), and two equivalent F(4) atoms to form FeO2F4 octahedra that share corners with four equivalent Fe(4)O4F2 octahedra,  a cornercorner with one Fe(5)O3F tetrahedra, edges with two equivalent Fe(2)O2F4 octahedra, and edges with four equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. In the third Fe site, Fe(3) is bonded to one O(2), one O(5), two equivalent F(2), and two equivalent F(5) atoms to form FeO2F4 octahedra that share corners with four equivalent Fe(6)O3F3 octahedra, corners with four equivalent Fe(5)O3F tetrahedra, and edges with two equivalent Fe(3)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(3), two equivalent O(6), one F(1), and one F(6) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra, edges with two equivalent Fe(4)O4F2 octahedra, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-56°. In the fifth Fe site, Fe(5) is bonded to one O(4), two equivalent O(5), and one F(2) atom to form FeO3F tetrahedra that share  a cornercorner with one Fe(2)O2F4 octahedra, corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(3)O2F4 octahedra, and corners with two equivalent Fe(5)O3F tetrahedra. The corner-sharing octahedral tilt angles range from 50-64°. In the sixth Fe site, Fe(6) is bonded to one O(1), two equivalent O(2), one F(5), and two equivalent F(3) atoms to form FeO3F3 octahedra that share corners with four equivalent Fe(3)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra, and edges with two equivalent Fe(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(6) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(6) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(4) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Fe(2), and one Fe(5) atom to form distorted OMg2Fe2 tetrahedra that share corners with two equivalent O(4)Mg2Fe2 tetrahedra, corners with three equivalent O(6)Mg2Fe3 trigonal bipyramids, and  an edgeedge with one O(6)Mg2Fe3 trigonal bipyramid. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(5) atoms. In the sixth O site, O(6) is bonded to two equivalent Mg(1), one Fe(2), and two equivalent Fe(4) atoms to form distorted OMg2Fe3 trigonal bipyramids that share corners with three equivalent O(4)Mg2Fe2 tetrahedra,  an edgeedge with one O(4)Mg2Fe2 tetrahedra, and edges with two equivalent O(6)Mg2Fe3 trigonal bipyramids. There are six inequivalent F sites. In the first F site, F(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(4), and two equivalent Fe(2) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(5) and two equivalent Fe(3) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(6) atoms. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Fe(2) atoms. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Fe(6) and two equivalent Fe(3) atoms. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Fe(4) and two equivalent Fe(1) atoms.
MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to two equivalent O(4), two equivalent O(6), one F(1), and one F(4) atom to form distorted MgO4F2 octahedra that share corners with two equivalent Fe(4)O4F2 octahedra, corners with two equivalent Fe(5)O3F tetrahedra, edges with two equivalent Mg(1)O4F2 octahedra, edges with four equivalent Fe(2)O2F4 octahedra, and  a faceface with one Fe(4)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-38°. There is one shorter (2.01 Å) and one longer (2.02 Å) Mg(1)-O(4) bond length. There is one shorter (2.30 Å) and one longer (2.32 Å) Mg(1)-O(6) bond length. The Mg(1)-F(1) bond length is 2.03 Å. The Mg(1)-F(4) bond length is 1.92 Å. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(1), one F(3), and two equivalent F(6) atoms to form FeO3F3 octahedra that share corners with four equivalent Fe(6)O3F3 octahedra, corners with four equivalent Fe(4)O4F2 octahedra, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-55°. The Fe(1)-O(3) bond length is 1.97 Å. Both Fe(1)-O(1) bond lengths are 1.93 Å. The Fe(1)-F(3) bond length is 2.13 Å. Both Fe(1)-F(6) bond lengths are 2.24 Å. In the second Fe site, Fe(2) is bonded to one O(4), one O(6), two equivalent F(1), and two equivalent F(4) atoms to form FeO2F4 octahedra that share corners with four equivalent Fe(4)O4F2 octahedra,  a cornercorner with one Fe(5)O3F tetrahedra, edges with two equivalent Fe(2)O2F4 octahedra, and edges with four equivalent Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. The Fe(2)-O(4) bond length is 2.07 Å. The Fe(2)-O(6) bond length is 2.02 Å. There is one shorter (2.15 Å) and one longer (2.16 Å) Fe(2)-F(1) bond length. Both Fe(2)-F(4) bond lengths are 2.14 Å. In the third Fe site, Fe(3) is bonded to one O(2), one O(5), two equivalent F(2), and two equivalent F(5) atoms to form FeO2F4 octahedra that share corners with four equivalent Fe(6)O3F3 octahedra, corners with four equivalent Fe(5)O3F tetrahedra, and edges with two equivalent Fe(3)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. The Fe(3)-O(2) bond length is 2.01 Å. The Fe(3)-O(5) bond length is 2.07 Å. Both Fe(3)-F(2) bond lengths are 2.26 Å. Both Fe(3)-F(5) bond lengths are 2.15 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(3), two equivalent O(6), one F(1), and one F(6) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra, edges with two equivalent Fe(4)O4F2 octahedra, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 37-56°. There is one shorter (1.95 Å) and one longer (1.96 Å) Fe(4)-O(3) bond length. There is one shorter (2.12 Å) and one longer (2.22 Å) Fe(4)-O(6) bond length. The Fe(4)-F(1) bond length is 2.23 Å. The Fe(4)-F(6) bond length is 2.06 Å. In the fifth Fe site, Fe(5) is bonded to one O(4), two equivalent O(5), and one F(2) atom to form FeO3F tetrahedra that share  a cornercorner with one Fe(2)O2F4 octahedra, corners with two equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(3)O2F4 octahedra, and corners with two equivalent Fe(5)O3F tetrahedra. The corner-sharing octahedral tilt angles range from 50-64°. The Fe(5)-O(4) bond length is 1.89 Å. There is one shorter (1.87 Å) and one longer (1.88 Å) Fe(5)-O(5) bond length. The Fe(5)-F(2) bond length is 1.93 Å. In the sixth Fe site, Fe(6) is bonded to one O(1), two equivalent O(2), one F(5), and two equivalent F(3) atoms to form FeO3F3 octahedra that share corners with four equivalent Fe(3)O2F4 octahedra, corners with four equivalent Fe(1)O3F3 octahedra, and edges with two equivalent Fe(6)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-56°. The Fe(6)-O(1) bond length is 2.01 Å. Both Fe(6)-O(2) bond lengths are 1.93 Å. The Fe(6)-F(5) bond length is 2.06 Å. There is one shorter (2.20 Å) and one longer (2.21 Å) Fe(6)-F(3) bond length. There are six inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(6) and two equivalent Fe(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(6) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(4) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Fe(2), and one Fe(5) atom to form distorted OMg2Fe2 tetrahedra that share corners with two equivalent O(4)Mg2Fe2 tetrahedra, corners with three equivalent O(6)Mg2Fe3 trigonal bipyramids, and  an edgeedge with one O(6)Mg2Fe3 trigonal bipyramid. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(5) atoms. In the sixth O site, O(6) is bonded to two equivalent Mg(1), one Fe(2), and two equivalent Fe(4) atoms to form distorted OMg2Fe3 trigonal bipyramids that share corners with three equivalent O(4)Mg2Fe2 tetrahedra,  an edgeedge with one O(4)Mg2Fe2 tetrahedra, and edges with two equivalent O(6)Mg2Fe3 trigonal bipyramids. There are six inequivalent F sites. In the first F site, F(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(4), and two equivalent Fe(2) atoms. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(5) and two equivalent Fe(3) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(6) atoms. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Fe(2) atoms. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Fe(6) and two equivalent Fe(3) atoms. In the sixth F site, F(6) is bonded in a distorted T-shaped geometry to one Fe(4) and two equivalent Fe(1) atoms.