MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(4), two equivalent O(1), one F(2), and two equivalent F(6) atoms to form MgO3F3 octahedra that share corners with two equivalent Fe(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, edges with two equivalent Fe(4)O3F3 octahedra, edges with two equivalent Fe(5)O3F3 octahedra, and  a faceface with one Fe(2)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-45°. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(6), one F(3), and two equivalent F(1) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the second Fe site, Fe(2) is bonded to one O(4), two equivalent O(1), one F(4), and two equivalent F(5) atoms to form FeO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F3 octahedra, corners with two equivalent Fe(6)O3F3 octahedra, corners with four equivalent Fe(4)O3F3 octahedra, edges with two equivalent Fe(2)O3F3 octahedra, and  a faceface with one Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(2), and two equivalent F(6) atoms. In the fourth Fe site, Fe(4) is bonded to one O(1), two equivalent O(3), one F(5), and two equivalent F(2) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra, corners with four equivalent Fe(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. In the fifth Fe site, Fe(5) is bonded to one O(2), two equivalent O(4), one F(6), and two equivalent F(3) atoms to form distorted FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(5)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 50-54°. In the sixth Fe site, Fe(6) is bonded to one O(6), two equivalent O(5), one F(1), and two equivalent F(4) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Fe(4), and two equivalent Fe(2) atoms to form distorted OMg2Fe3 trigonal bipyramids that share edges with two equivalent O(4)MgFe3 tetrahedra and edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(3) 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 one Mg(1), one Fe(2), and two equivalent Fe(5) atoms to form distorted OMgFe3 tetrahedra that share corners with two equivalent O(4)MgFe3 tetrahedra and edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Fe(3) and two equivalent Fe(6) atoms. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(6) and two equivalent Fe(1) atoms. There are six inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Fe(6) and two equivalent Fe(1) atoms. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Fe(4) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(5) atoms. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Fe(2) and two equivalent Fe(6) atoms. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Fe(4) and two equivalent Fe(2) atoms. In the sixth F site, F(6) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Fe(5), and two equivalent Fe(3) atoms.
MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(4), two equivalent O(1), one F(2), and two equivalent F(6) atoms to form MgO3F3 octahedra that share corners with two equivalent Fe(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, edges with two equivalent Fe(4)O3F3 octahedra, edges with two equivalent Fe(5)O3F3 octahedra, and  a faceface with one Fe(2)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-45°. The Mg(1)-O(4) bond length is 2.00 Å. Both Mg(1)-O(1) bond lengths are 2.13 Å. The Mg(1)-F(2) bond length is 1.95 Å. There is one shorter (2.08 Å) and one longer (2.09 Å) Mg(1)-F(6) bond length. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(3), two equivalent O(6), one F(3), and two equivalent F(1) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. The Fe(1)-O(3) bond length is 1.96 Å. There is one shorter (1.96 Å) and one longer (1.97 Å) Fe(1)-O(6) bond length. The Fe(1)-F(3) bond length is 2.24 Å. There is one shorter (2.11 Å) and one longer (2.12 Å) Fe(1)-F(1) bond length. In the second Fe site, Fe(2) is bonded to one O(4), two equivalent O(1), one F(4), and two equivalent F(5) atoms to form FeO3F3 octahedra that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(5)O3F3 octahedra, corners with two equivalent Fe(6)O3F3 octahedra, corners with four equivalent Fe(4)O3F3 octahedra, edges with two equivalent Fe(2)O3F3 octahedra, and  a faceface with one Mg(1)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 44-54°. The Fe(2)-O(4) bond length is 2.19 Å. There is one shorter (2.23 Å) and one longer (2.27 Å) Fe(2)-O(1) bond length. The Fe(2)-F(4) bond length is 2.14 Å. There is one shorter (2.10 Å) and one longer (2.12 Å) Fe(2)-F(5) bond length. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(2), and two equivalent F(6) atoms. The Fe(3)-O(5) bond length is 1.96 Å. Both Fe(3)-O(2) bond lengths are 1.94 Å. There is one shorter (2.48 Å) and one longer (2.55 Å) Fe(3)-F(6) bond length. In the fourth Fe site, Fe(4) is bonded to one O(1), two equivalent O(3), one F(5), and two equivalent F(2) atoms to form FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra, corners with four equivalent Fe(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(4)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 47-54°. The Fe(4)-O(1) bond length is 1.99 Å. Both Fe(4)-O(3) bond lengths are 1.93 Å. The Fe(4)-F(5) bond length is 2.10 Å. There is one shorter (2.16 Å) and one longer (2.17 Å) Fe(4)-F(2) bond length. In the fifth Fe site, Fe(5) is bonded to one O(2), two equivalent O(4), one F(6), and two equivalent F(3) atoms to form distorted FeO3F3 octahedra that share corners with two equivalent Fe(1)O3F3 octahedra, corners with two equivalent Fe(2)O3F3 octahedra, edges with two equivalent Mg(1)O3F3 octahedra, and edges with two equivalent Fe(5)O3F3 octahedra. The corner-sharing octahedral tilt angles range from 50-54°. The Fe(5)-O(2) bond length is 1.84 Å. Both Fe(5)-O(4) bond lengths are 1.97 Å. The Fe(5)-F(6) bond length is 2.39 Å. There is one shorter (2.17 Å) and one longer (2.18 Å) Fe(5)-F(3) bond length. In the sixth Fe site, Fe(6) is bonded to one O(6), two equivalent O(5), one F(1), and two equivalent F(4) atoms to form a mixture of edge and corner-sharing FeO3F3 octahedra. The corner-sharing octahedral tilt angles range from 46-54°. The Fe(6)-O(6) bond length is 2.00 Å. Both Fe(6)-O(5) bond lengths are 1.92 Å. The Fe(6)-F(1) bond length is 2.30 Å. There is one shorter (2.13 Å) and one longer (2.14 Å) Fe(6)-F(4) bond length. There are six inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Fe(4), and two equivalent Fe(2) atoms to form distorted OMg2Fe3 trigonal bipyramids that share edges with two equivalent O(4)MgFe3 tetrahedra and edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(3) 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 one Mg(1), one Fe(2), and two equivalent Fe(5) atoms to form distorted OMgFe3 tetrahedra that share corners with two equivalent O(4)MgFe3 tetrahedra and edges with two equivalent O(1)Mg2Fe3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Fe(3) and two equivalent Fe(6) atoms. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Fe(6) and two equivalent Fe(1) atoms. There are six inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Fe(6) and two equivalent Fe(1) atoms. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Fe(4) atoms. In the third F site, F(3) is bonded in a distorted T-shaped geometry to one Fe(1) and two equivalent Fe(5) atoms. In the fourth F site, F(4) is bonded in a distorted T-shaped geometry to one Fe(2) and two equivalent Fe(6) atoms. In the fifth F site, F(5) is bonded in a distorted T-shaped geometry to one Fe(4) and two equivalent Fe(2) atoms. In the sixth F site, F(6) is bonded in a 5-coordinate geometry to two equivalent Mg(1), one Fe(5), and two equivalent Fe(3) atoms.