MgFe6(O5F)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(6), one O(7), two equivalent O(8), and two equivalent F(1) atoms to form distorted MgO4F2 octahedra that share corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(5)O5 square pyramids,  a cornercorner with one Fe(3)O4 tetrahedra, edges with two equivalent Mg(1)O4F2 octahedra, edges with two equivalent Fe(4)O4F2 octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles are 33°. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), two equivalent O(5), and two equivalent F(2) atoms to form FeO4F2 octahedra that share corners with two equivalent Fe(4)O4F2 octahedra, corners with four equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(5)O5 square pyramids, and edges with two equivalent Fe(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. In the second Fe site, Fe(2) is bonded to one O(4), one O(9), two equivalent O(1), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Fe(6)O6 octahedra, corners with four equivalent Fe(1)O4F2 octahedra, corners with two equivalent Fe(3)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. In the third Fe site, Fe(3) is bonded to one O(2), one O(6), and two equivalent O(4) atoms to form FeO4 tetrahedra that share  a cornercorner with one Mg(1)O4F2 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(5)O5 square pyramids, and corners with two equivalent Fe(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-79°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(10), two equivalent O(7), one F(1), and one F(2) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(6)O6 octahedra, edges with two equivalent Mg(1)O4F2 octahedra, and edges with two equivalent Fe(4)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. In the fifth Fe site, Fe(5) is bonded to one O(5), two equivalent O(2), and two equivalent O(6) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(3)O4 tetrahedra, and edges with two equivalent Fe(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 51-69°. In the sixth Fe site, Fe(6) is bonded to one O(10), one O(7), two equivalent O(8), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(4)O4F2 octahedra, edges with two equivalent Fe(6)O6 octahedra, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 33-53°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(5) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(3) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(1) atoms. In the sixth O site, O(6) is bonded to one Mg(1), one Fe(3), and two equivalent Fe(5) atoms to form corner-sharing OMgFe3 tetrahedra. In the seventh O site, O(7) is bonded to one Mg(1), one Fe(6), and two equivalent Fe(4) atoms to form distorted corner-sharing OMgFe3 tetrahedra. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Fe(6) atoms. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(6) atoms. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Fe(6) and two equivalent Fe(4) atoms. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one Fe(4) atom. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(4) and two equivalent Fe(1) atoms.
MgFe6(O5F)2 crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(6), one O(7), two equivalent O(8), and two equivalent F(1) atoms to form distorted MgO4F2 octahedra that share corners with two equivalent Fe(6)O6 octahedra, corners with two equivalent Fe(5)O5 square pyramids,  a cornercorner with one Fe(3)O4 tetrahedra, edges with two equivalent Mg(1)O4F2 octahedra, edges with two equivalent Fe(4)O4F2 octahedra, and  a faceface with one Fe(6)O6 octahedra. The corner-sharing octahedral tilt angles are 33°. The Mg(1)-O(6) bond length is 2.01 Å. The Mg(1)-O(7) bond length is 2.12 Å. Both Mg(1)-O(8) bond lengths are 2.15 Å. Both Mg(1)-F(1) bond lengths are 2.02 Å. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), two equivalent O(5), and two equivalent F(2) atoms to form FeO4F2 octahedra that share corners with two equivalent Fe(4)O4F2 octahedra, corners with four equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(5)O5 square pyramids, and edges with two equivalent Fe(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. The Fe(1)-O(1) bond length is 1.95 Å. The Fe(1)-O(3) bond length is 1.95 Å. Both Fe(1)-O(5) bond lengths are 1.94 Å. Both Fe(1)-F(2) bond lengths are 2.14 Å. In the second Fe site, Fe(2) is bonded to one O(4), one O(9), two equivalent O(1), and two equivalent O(3) atoms to form FeO6 octahedra that share corners with two equivalent Fe(6)O6 octahedra, corners with four equivalent Fe(1)O4F2 octahedra, corners with two equivalent Fe(3)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. The Fe(2)-O(4) bond length is 2.07 Å. The Fe(2)-O(9) bond length is 2.00 Å. Both Fe(2)-O(1) bond lengths are 1.97 Å. Both Fe(2)-O(3) bond lengths are 1.97 Å. In the third Fe site, Fe(3) is bonded to one O(2), one O(6), and two equivalent O(4) atoms to form FeO4 tetrahedra that share  a cornercorner with one Mg(1)O4F2 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(5)O5 square pyramids, and corners with two equivalent Fe(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-79°. The Fe(3)-O(2) bond length is 1.95 Å. The Fe(3)-O(6) bond length is 2.04 Å. Both Fe(3)-O(4) bond lengths are 1.87 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(10), two equivalent O(7), one F(1), and one F(2) atom to form distorted FeO4F2 octahedra that share corners with two equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(6)O6 octahedra, edges with two equivalent Mg(1)O4F2 octahedra, and edges with two equivalent Fe(4)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-53°. Both Fe(4)-O(10) bond lengths are 1.92 Å. Both Fe(4)-O(7) bond lengths are 1.96 Å. The Fe(4)-F(1) bond length is 2.43 Å. The Fe(4)-F(2) bond length is 2.05 Å. In the fifth Fe site, Fe(5) is bonded to one O(5), two equivalent O(2), and two equivalent O(6) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(3)O4 tetrahedra, and edges with two equivalent Fe(5)O5 square pyramids. The corner-sharing octahedral tilt angles range from 51-69°. The Fe(5)-O(5) bond length is 1.94 Å. Both Fe(5)-O(2) bond lengths are 1.99 Å. Both Fe(5)-O(6) bond lengths are 2.11 Å. In the sixth Fe site, Fe(6) is bonded to one O(10), one O(7), two equivalent O(8), and two equivalent O(9) atoms to form FeO6 octahedra that share corners with two equivalent Mg(1)O4F2 octahedra, corners with two equivalent Fe(2)O6 octahedra, corners with four equivalent Fe(4)O4F2 octahedra, edges with two equivalent Fe(6)O6 octahedra, and  a faceface with one Mg(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 33-53°. The Fe(6)-O(10) bond length is 1.95 Å. The Fe(6)-O(7) bond length is 2.04 Å. Both Fe(6)-O(8) bond lengths are 2.07 Å. Both Fe(6)-O(9) bond lengths are 1.95 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(5) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(3) atoms. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Fe(5) and two equivalent Fe(1) atoms. In the sixth O site, O(6) is bonded to one Mg(1), one Fe(3), and two equivalent Fe(5) atoms to form corner-sharing OMgFe3 tetrahedra. In the seventh O site, O(7) is bonded to one Mg(1), one Fe(6), and two equivalent Fe(4) atoms to form distorted corner-sharing OMgFe3 tetrahedra. In the eighth O site, O(8) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Fe(6) atoms. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(6) atoms. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Fe(6) and two equivalent Fe(4) atoms. There are two inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one Fe(4) atom. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Fe(4) and two equivalent Fe(1) atoms.