MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to two equivalent O(3), two equivalent O(6), one F(1), and one F(6) atom to form MgO4F2 octahedra that share corners with four equivalent Fe(4)O4F trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, edges with two equivalent Fe(2)O2F4 octahedra, edges with two equivalent Fe(1)O3F3 octahedra,  an edgeedge with one Fe(4)O4F trigonal bipyramid, and  a faceface with one Fe(4)O4F trigonal bipyramid. 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 distorted FeO3F3 octahedra that share corners with four equivalent Fe(6)O3F3 octahedra, corners with two equivalent Fe(4)O4F trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. 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(5)O4F2 octahedra, corners with four equivalent Fe(4)O4F trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, and edges with two equivalent Fe(2)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. 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)O4F2 octahedra, and edges with two equivalent Fe(3)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(3), two equivalent O(6), and one F(1) atom to form distorted FeO4F trigonal bipyramids that share corners with two equivalent Fe(1)O3F3 octahedra, corners with four equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(2)O2F4 octahedra,  an edgeedge with one Mg(1)O4F2 octahedra, edges with two equivalent Fe(4)O4F trigonal bipyramids, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 36-60°. In the fifth Fe site, Fe(5) is bonded to two equivalent O(4), two equivalent O(5), one F(2), and one F(4) atom to form FeO4F2 octahedra that share corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(3)O2F4 octahedra, and edges with two equivalent Fe(5)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. 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 45-54°. 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 to two equivalent Mg(1), one Fe(1), and two equivalent Fe(4) atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(5) atoms. In the fifth O site, O(5) is bonded in a distorted 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 a mixture of distorted corner and edge-sharing OMg2Fe3 square 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 Fe(4), and two equivalent Fe(2) atoms. In the second F site, F(2) is bonded in a distorted trigonal planar 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 distorted T-shaped geometry to one Fe(5) and two equivalent Fe(2) atoms. In the fifth F site, F(5) is bonded in a distorted trigonal planar geometry to one Fe(6) and two equivalent Fe(3) atoms. In the sixth F site, F(6) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Fe(1) atoms.
MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to two equivalent O(3), two equivalent O(6), one F(1), and one F(6) atom to form MgO4F2 octahedra that share corners with four equivalent Fe(4)O4F trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, edges with two equivalent Fe(2)O2F4 octahedra, edges with two equivalent Fe(1)O3F3 octahedra,  an edgeedge with one Fe(4)O4F trigonal bipyramid, and  a faceface with one Fe(4)O4F trigonal bipyramid. Both Mg(1)-O(3) bond lengths are 2.15 Å. Both Mg(1)-O(6) bond lengths are 2.09 Å. The Mg(1)-F(1) bond length is 1.94 Å. The Mg(1)-F(6) bond length is 1.98 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 distorted FeO3F3 octahedra that share corners with four equivalent Fe(6)O3F3 octahedra, corners with two equivalent Fe(4)O4F trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, and edges with two equivalent Fe(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 45-54°. The Fe(1)-O(3) bond length is 1.98 Å. There is one shorter (1.92 Å) and one longer (1.93 Å) Fe(1)-O(1) bond length. The Fe(1)-F(3) bond length is 2.15 Å. Both Fe(1)-F(6) bond lengths are 2.19 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(5)O4F2 octahedra, corners with four equivalent Fe(4)O4F trigonal bipyramids, edges with two equivalent Mg(1)O4F2 octahedra, and edges with two equivalent Fe(2)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. The Fe(2)-O(4) bond length is 1.97 Å. The Fe(2)-O(6) bond length is 2.17 Å. There is one shorter (2.31 Å) and one longer (2.32 Å) Fe(2)-F(1) bond length. There is one shorter (2.12 Å) and one longer (2.13 Å) Fe(2)-F(4) bond length. 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)O4F2 octahedra, and edges with two equivalent Fe(3)O2F4 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. The Fe(3)-O(2) bond length is 2.05 Å. The Fe(3)-O(5) bond length is 1.86 Å. Both Fe(3)-F(2) bond lengths are 2.01 Å. Both Fe(3)-F(5) bond lengths are 2.10 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(3), two equivalent O(6), and one F(1) atom to form distorted FeO4F trigonal bipyramids that share corners with two equivalent Fe(1)O3F3 octahedra, corners with four equivalent Mg(1)O4F2 octahedra, corners with four equivalent Fe(2)O2F4 octahedra,  an edgeedge with one Mg(1)O4F2 octahedra, edges with two equivalent Fe(4)O4F trigonal bipyramids, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 36-60°. There is one shorter (2.16 Å) and one longer (2.17 Å) Fe(4)-O(3) bond length. Both Fe(4)-O(6) bond lengths are 2.10 Å. The Fe(4)-F(1) bond length is 2.18 Å. In the fifth Fe site, Fe(5) is bonded to two equivalent O(4), two equivalent O(5), one F(2), and one F(4) atom to form FeO4F2 octahedra that share corners with four equivalent Fe(2)O2F4 octahedra, corners with four equivalent Fe(3)O2F4 octahedra, and edges with two equivalent Fe(5)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 48-52°. Both Fe(5)-O(4) bond lengths are 1.95 Å. Both Fe(5)-O(5) bond lengths are 2.05 Å. The Fe(5)-F(2) bond length is 2.44 Å. The Fe(5)-F(4) bond length is 2.07 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 45-54°. The Fe(6)-O(1) bond length is 2.00 Å. Both Fe(6)-O(2) bond lengths are 1.92 Å. The Fe(6)-F(5) bond length is 2.26 Å. Both Fe(6)-F(3) bond lengths are 2.15 Å. 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 to two equivalent Mg(1), one Fe(1), and two equivalent Fe(4) atoms to form a mixture of distorted corner and edge-sharing OMg2Fe3 trigonal bipyramids. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(5) atoms. In the fifth O site, O(5) is bonded in a distorted 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 a mixture of distorted corner and edge-sharing OMg2Fe3 square 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 Fe(4), and two equivalent Fe(2) atoms. In the second F site, F(2) is bonded in a distorted trigonal planar 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 distorted T-shaped geometry to one Fe(5) and two equivalent Fe(2) atoms. In the fifth F site, F(5) is bonded in a distorted trigonal planar geometry to one Fe(6) and two equivalent Fe(3) atoms. In the sixth F site, F(6) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Fe(1) atoms.