MgFe6(O5F)2 crystallizes in the monoclinic P2/m space group. Mg(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(2)O5 square pyramids, edges with two equivalent Mg(1)O6 octahedra, and faces with two equivalent Fe(1)O4F2 octahedra. The corner-sharing octahedral tilt angles are 33°. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent F(1) atoms to form FeO4F2 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(3)O4F2 octahedra, corners with four equivalent Fe(2)O5 square pyramids, edges with two equivalent Fe(1)O4F2 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-45°. In the second Fe site, Fe(2) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, corners with four equivalent Fe(1)O4F2 octahedra, and edges with two equivalent Fe(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-68°. In the third Fe site, Fe(3) is bonded to four equivalent O(4) and two equivalent F(1) atoms to form FeO4F2 octahedra that share corners with four equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(4)O6 octahedra, and edges with two equivalent Fe(3)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. In the fourth Fe site, Fe(4) is bonded to two equivalent O(4) and four equivalent O(5) atoms to form FeO6 octahedra that share corners with four equivalent Fe(3)O4F2 octahedra, corners with four equivalent Fe(2)O5 square pyramids, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted corner-sharing OMgFe3 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(4) and two equivalent Fe(3) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(2) and two equivalent Fe(4) atoms. F(1) is bonded in a distorted T-shaped geometry to one Fe(3) and two equivalent Fe(1) atoms.
MgFe6(O5F)2 crystallizes in the monoclinic P2/m space group. Mg(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form MgO6 octahedra that share corners with four equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(2)O5 square pyramids, edges with two equivalent Mg(1)O6 octahedra, and faces with two equivalent Fe(1)O4F2 octahedra. The corner-sharing octahedral tilt angles are 33°. Both Mg(1)-O(1) bond lengths are 2.10 Å. All Mg(1)-O(3) bond lengths are 2.12 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent F(1) atoms to form FeO4F2 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(3)O4F2 octahedra, corners with four equivalent Fe(2)O5 square pyramids, edges with two equivalent Fe(1)O4F2 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-45°. The Fe(1)-O(1) bond length is 2.14 Å. The Fe(1)-O(2) bond length is 1.93 Å. Both Fe(1)-O(3) bond lengths are 1.99 Å. Both Fe(1)-F(1) bond lengths are 2.07 Å. In the second Fe site, Fe(2) is bonded to one O(5), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, corners with four equivalent Fe(1)O4F2 octahedra, and edges with two equivalent Fe(2)O5 square pyramids. The corner-sharing octahedral tilt angles range from 49-68°. The Fe(2)-O(5) bond length is 1.92 Å. Both Fe(2)-O(1) bond lengths are 1.98 Å. Both Fe(2)-O(2) bond lengths are 1.96 Å. In the third Fe site, Fe(3) is bonded to four equivalent O(4) and two equivalent F(1) atoms to form FeO4F2 octahedra that share corners with four equivalent Fe(1)O4F2 octahedra, corners with four equivalent Fe(4)O6 octahedra, and edges with two equivalent Fe(3)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 45-50°. All Fe(3)-O(4) bond lengths are 1.92 Å. Both Fe(3)-F(1) bond lengths are 2.17 Å. In the fourth Fe site, Fe(4) is bonded to two equivalent O(4) and four equivalent O(5) atoms to form FeO6 octahedra that share corners with four equivalent Fe(3)O4F2 octahedra, corners with four equivalent Fe(2)O5 square pyramids, and edges with two equivalent Fe(4)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. Both Fe(4)-O(4) bond lengths are 2.05 Å. All Fe(4)-O(5) bond lengths are 1.93 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), and two equivalent Fe(2) atoms to form distorted corner-sharing OMgFe3 tetrahedra. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(4) and two equivalent Fe(3) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(2) and two equivalent Fe(4) atoms. F(1) is bonded in a distorted T-shaped geometry to one Fe(3) and two equivalent Fe(1) atoms.