MgFe6(O5F)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(2), one O(5), one O(7), one O(8), and one F(1) atom to form MgO5F octahedra that share corners with two equivalent Fe(1)O5 square pyramids,  a cornercorner with one Fe(5)O5 trigonal bipyramid,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(6)O5F octahedra, edges with two equivalent Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(5)O5 trigonal bipyramid. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(4), one O(8), and one O(9) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(3)O4F2 octahedra, corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with three equivalent Fe(6)O5F octahedra, and  an edgeedge with one Fe(5)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 43-60°. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(5), one O(6), one O(8), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5 square pyramids, corners with three equivalent Fe(5)O5 trigonal bipyramids,  an edgeedge with one Mg(1)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(6)O5F octahedra. In the third Fe site, Fe(3) is bonded to one O(2), one O(4), one O(5), one O(7), one F(1), and one F(2) atom to form FeO4F2 octahedra that share  a cornercorner with one Fe(1)O5 square pyramid, corners with two equivalent Fe(5)O5 trigonal bipyramids,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(6)O5F octahedra, and edges with two equivalent Mg(1)O5F octahedra. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(3), one O(7), and one O(9) atom. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(2), one O(6), one O(7), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(3)O4F2 octahedra, corners with three equivalent Fe(2)O5F octahedra,  an edgeedge with one Mg(1)O5F octahedra, and  an edgeedge with one Fe(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 43-61°. In the sixth Fe site, Fe(6) is bonded to one O(10), one O(3), one O(4), one O(6), one O(9), and one F(1) atom to form FeO5F octahedra that share corners with three equivalent Fe(1)O5 square pyramids,  a cornercorner with one Fe(5)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(2)O5F octahedra. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(1), one Fe(2), and one Fe(5) atom. In the second O site, O(2) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Fe(5) atom to form a mixture of edge and corner-sharing OMgFe3 trigonal pyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(6) atom. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Fe(2), and one Fe(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(5), and one Fe(6) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Fe(5) atom to form a mixture of edge and corner-sharing OMgFe3 trigonal pyramids. In the eighth O site, O(8) is bonded in a see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(5) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Fe(1), one Fe(4), and one Fe(6) atom. In the tenth O site, O(10) is bonded to one Mg(1), one Fe(1), one Fe(4), and one Fe(6) atom to form a mixture of edge and corner-sharing OMgFe3 trigonal pyramids. There are two inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(3), and one Fe(6) atom. In the second F site, F(2) is bonded in an L-shaped geometry to one Fe(2) and one Fe(3) atom.
MgFe6(O5F)2 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(10), one O(2), one O(5), one O(7), one O(8), and one F(1) atom to form MgO5F octahedra that share corners with two equivalent Fe(1)O5 square pyramids,  a cornercorner with one Fe(5)O5 trigonal bipyramid,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(6)O5F octahedra, edges with two equivalent Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(5)O5 trigonal bipyramid. The Mg(1)-O(10) bond length is 2.17 Å. The Mg(1)-O(2) bond length is 2.06 Å. The Mg(1)-O(5) bond length is 1.99 Å. The Mg(1)-O(7) bond length is 2.10 Å. The Mg(1)-O(8) bond length is 2.20 Å. The Mg(1)-F(1) bond length is 1.97 Å. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(10), one O(4), one O(8), and one O(9) atom to form distorted FeO5 square pyramids that share  a cornercorner with one Fe(3)O4F2 octahedra, corners with two equivalent Mg(1)O5F octahedra, corners with two equivalent Fe(2)O5F octahedra, corners with three equivalent Fe(6)O5F octahedra, and  an edgeedge with one Fe(5)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 43-60°. The Fe(1)-O(1) bond length is 1.98 Å. The Fe(1)-O(10) bond length is 2.03 Å. The Fe(1)-O(4) bond length is 1.98 Å. The Fe(1)-O(8) bond length is 2.06 Å. The Fe(1)-O(9) bond length is 1.96 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(5), one O(6), one O(8), and one F(2) atom to form FeO5F octahedra that share corners with two equivalent Fe(1)O5 square pyramids, corners with three equivalent Fe(5)O5 trigonal bipyramids,  an edgeedge with one Mg(1)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(6)O5F octahedra. The Fe(2)-O(1) bond length is 1.97 Å. The Fe(2)-O(3) bond length is 1.91 Å. The Fe(2)-O(5) bond length is 1.88 Å. The Fe(2)-O(6) bond length is 1.99 Å. The Fe(2)-O(8) bond length is 2.10 Å. The Fe(2)-F(2) bond length is 2.07 Å. In the third Fe site, Fe(3) is bonded to one O(2), one O(4), one O(5), one O(7), one F(1), and one F(2) atom to form FeO4F2 octahedra that share  a cornercorner with one Fe(1)O5 square pyramid, corners with two equivalent Fe(5)O5 trigonal bipyramids,  an edgeedge with one Fe(2)O5F octahedra,  an edgeedge with one Fe(6)O5F octahedra, and edges with two equivalent Mg(1)O5F octahedra. The Fe(3)-O(2) bond length is 2.05 Å. The Fe(3)-O(4) bond length is 1.96 Å. The Fe(3)-O(5) bond length is 1.91 Å. The Fe(3)-O(7) bond length is 2.08 Å. The Fe(3)-F(1) bond length is 2.07 Å. The Fe(3)-F(2) bond length is 2.04 Å. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(3), one O(7), and one O(9) atom. The Fe(4)-O(10) bond length is 2.05 Å. The Fe(4)-O(2) bond length is 2.05 Å. The Fe(4)-O(3) bond length is 1.92 Å. The Fe(4)-O(7) bond length is 2.00 Å. The Fe(4)-O(9) bond length is 1.95 Å. In the fifth Fe site, Fe(5) is bonded to one O(1), one O(2), one O(6), one O(7), and one O(8) atom to form distorted FeO5 trigonal bipyramids that share  a cornercorner with one Mg(1)O5F octahedra,  a cornercorner with one Fe(6)O5F octahedra, corners with two equivalent Fe(3)O4F2 octahedra, corners with three equivalent Fe(2)O5F octahedra,  an edgeedge with one Mg(1)O5F octahedra, and  an edgeedge with one Fe(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 43-61°. The Fe(5)-O(1) bond length is 1.95 Å. The Fe(5)-O(2) bond length is 1.97 Å. The Fe(5)-O(6) bond length is 1.90 Å. The Fe(5)-O(7) bond length is 1.99 Å. The Fe(5)-O(8) bond length is 2.02 Å. In the sixth Fe site, Fe(6) is bonded to one O(10), one O(3), one O(4), one O(6), one O(9), and one F(1) atom to form FeO5F octahedra that share corners with three equivalent Fe(1)O5 square pyramids,  a cornercorner with one Fe(5)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O5F octahedra,  an edgeedge with one Fe(3)O4F2 octahedra, and  an edgeedge with one Fe(2)O5F octahedra. The Fe(6)-O(10) bond length is 2.08 Å. The Fe(6)-O(3) bond length is 2.06 Å. The Fe(6)-O(4) bond length is 1.97 Å. The Fe(6)-O(6) bond length is 1.92 Å. The Fe(6)-O(9) bond length is 1.98 Å. The Fe(6)-F(1) bond length is 2.13 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), one Fe(2), and one Fe(5) atom. In the second O site, O(2) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Fe(5) atom to form a mixture of edge and corner-sharing OMgFe3 trigonal pyramids. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(4), and one Fe(6) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(6) atom. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Mg(1), one Fe(2), and one Fe(3) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Fe(2), one Fe(5), and one Fe(6) atom. In the seventh O site, O(7) is bonded to one Mg(1), one Fe(3), one Fe(4), and one Fe(5) atom to form a mixture of edge and corner-sharing OMgFe3 trigonal pyramids. In the eighth O site, O(8) is bonded in a see-saw-like geometry to one Mg(1), one Fe(1), one Fe(2), and one Fe(5) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Fe(1), one Fe(4), and one Fe(6) atom. In the tenth O site, O(10) is bonded to one Mg(1), one Fe(1), one Fe(4), and one Fe(6) atom to form a mixture of edge and corner-sharing OMgFe3 trigonal pyramids. There are two inequivalent F sites. In the first F site, F(1) is bonded in a distorted T-shaped geometry to one Mg(1), one Fe(3), and one Fe(6) atom. In the second F site, F(2) is bonded in an L-shaped geometry to one Fe(2) and one Fe(3) atom.