MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(4), one O(6), one F(1), one F(4), and one F(6) atom to form MgO3F3 octahedra that share corners with two equivalent Fe(3)O3F2 square pyramids,  a cornercorner with one Fe(6)O3F2 trigonal bipyramid, corners with two equivalent Fe(1)O3F2 trigonal bipyramids,  an edgeedge with one Fe(2)O3F2 trigonal bipyramid,  an edgeedge with one Fe(6)O3F2 trigonal bipyramid, and  a faceface with one Fe(2)O3F2 trigonal bipyramid. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(5), one O(6), one F(1), and one F(5) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(4)O3F2 square pyramids,  an edgeedge with one Fe(3)O3F2 square pyramid, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 32-51°. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one O(6), one F(1), and one F(6) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Fe(6)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra,  an edgeedge with one Fe(3)O3F2 square pyramid,  an edgeedge with one Fe(1)O3F2 trigonal bipyramid, and  a faceface with one Mg(1)O3F3 octahedra. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), one F(5), and one F(6) atom to form distorted FeO3F2 square pyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(4)O3F2 square pyramids, corners with two equivalent Fe(6)O3F2 trigonal bipyramids,  an edgeedge with one Fe(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 33-49°. In the fourth Fe site, Fe(4) is bonded to one O(2), one O(3), one O(5), one F(2), and one F(3) atom to form a mixture of distorted corner and edge-sharing FeO3F2 square pyramids. In the fifth Fe site, Fe(5) is bonded in a 5-coordinate geometry to one O(4), one O(5), one O(6), one F(2), and one F(4) atom. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(3), one O(4), one F(3), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share  a cornercorner with one Mg(1)O3F3 octahedra, corners with two equivalent Fe(3)O3F2 square pyramids, corners with two equivalent Fe(2)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra, and  an edgeedge with one Fe(4)O3F2 square pyramid. The corner-sharing octahedral tilt angles are 65°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(3), and one Fe(6) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Fe(6) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Fe(5), and one Fe(6) atom to form a mixture of distorted corner and edge-sharing OMgFe3 tetrahedra. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(4), and one Fe(5) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Fe(1), one Fe(2), and one Fe(5) atom to form a mixture of distorted corner and edge-sharing OMgFe3 trigonal pyramids. There are six inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(2) atom. In the second F site, F(2) is bonded in an L-shaped geometry to one Fe(4) and one Fe(5) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Fe(4) and one Fe(6) atom. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(5), and one Fe(6) atom. In the fifth F site, F(5) is bonded in a water-like geometry to one Fe(1) and one Fe(3) atom. In the sixth F site, F(6) is bonded in a T-shaped geometry to one Mg(1), one Fe(2), and one Fe(3) atom.
MgFe6(OF)6 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(4), one O(6), one F(1), one F(4), and one F(6) atom to form MgO3F3 octahedra that share corners with two equivalent Fe(3)O3F2 square pyramids,  a cornercorner with one Fe(6)O3F2 trigonal bipyramid, corners with two equivalent Fe(1)O3F2 trigonal bipyramids,  an edgeedge with one Fe(2)O3F2 trigonal bipyramid,  an edgeedge with one Fe(6)O3F2 trigonal bipyramid, and  a faceface with one Fe(2)O3F2 trigonal bipyramid. The Mg(1)-O(1) bond length is 2.19 Å. The Mg(1)-O(4) bond length is 2.01 Å. The Mg(1)-O(6) bond length is 2.06 Å. The Mg(1)-F(1) bond length is 2.22 Å. The Mg(1)-F(4) bond length is 1.95 Å. The Mg(1)-F(6) bond length is 2.18 Å. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(5), one O(6), one F(1), and one F(5) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(4)O3F2 square pyramids,  an edgeedge with one Fe(3)O3F2 square pyramid, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 32-51°. The Fe(1)-O(2) bond length is 2.00 Å. The Fe(1)-O(5) bond length is 1.90 Å. The Fe(1)-O(6) bond length is 1.95 Å. The Fe(1)-F(1) bond length is 2.23 Å. The Fe(1)-F(5) bond length is 2.01 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(4), one O(6), one F(1), and one F(6) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Fe(6)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra,  an edgeedge with one Fe(3)O3F2 square pyramid,  an edgeedge with one Fe(1)O3F2 trigonal bipyramid, and  a faceface with one Mg(1)O3F3 octahedra. The Fe(2)-O(1) bond length is 2.09 Å. The Fe(2)-O(4) bond length is 2.05 Å. The Fe(2)-O(6) bond length is 1.99 Å. The Fe(2)-F(1) bond length is 2.12 Å. The Fe(2)-F(6) bond length is 2.09 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(3), one F(5), and one F(6) atom to form distorted FeO3F2 square pyramids that share corners with two equivalent Mg(1)O3F3 octahedra, corners with two equivalent Fe(4)O3F2 square pyramids, corners with two equivalent Fe(6)O3F2 trigonal bipyramids,  an edgeedge with one Fe(1)O3F2 trigonal bipyramid, and  an edgeedge with one Fe(2)O3F2 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 33-49°. The Fe(3)-O(1) bond length is 2.01 Å. The Fe(3)-O(2) bond length is 1.93 Å. The Fe(3)-O(3) bond length is 1.92 Å. The Fe(3)-F(5) bond length is 2.03 Å. The Fe(3)-F(6) bond length is 2.12 Å. In the fourth Fe site, Fe(4) is bonded to one O(2), one O(3), one O(5), one F(2), and one F(3) atom to form a mixture of distorted corner and edge-sharing FeO3F2 square pyramids. The Fe(4)-O(2) bond length is 1.93 Å. The Fe(4)-O(3) bond length is 2.01 Å. The Fe(4)-O(5) bond length is 1.94 Å. The Fe(4)-F(2) bond length is 1.96 Å. The Fe(4)-F(3) bond length is 2.03 Å. In the fifth Fe site, Fe(5) is bonded in a 5-coordinate geometry to one O(4), one O(5), one O(6), one F(2), and one F(4) atom. The Fe(5)-O(4) bond length is 2.06 Å. The Fe(5)-O(5) bond length is 2.00 Å. The Fe(5)-O(6) bond length is 2.13 Å. The Fe(5)-F(2) bond length is 2.12 Å. The Fe(5)-F(4) bond length is 2.24 Å. In the sixth Fe site, Fe(6) is bonded to one O(1), one O(3), one O(4), one F(3), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share  a cornercorner with one Mg(1)O3F3 octahedra, corners with two equivalent Fe(3)O3F2 square pyramids, corners with two equivalent Fe(2)O3F2 trigonal bipyramids,  an edgeedge with one Mg(1)O3F3 octahedra, and  an edgeedge with one Fe(4)O3F2 square pyramid. The corner-sharing octahedral tilt angles are 65°. The Fe(6)-O(1) bond length is 1.94 Å. The Fe(6)-O(3) bond length is 1.93 Å. The Fe(6)-O(4) bond length is 1.90 Å. The Fe(6)-F(3) bond length is 2.00 Å. The Fe(6)-F(4) bond length is 2.15 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Fe(2), one Fe(3), and one Fe(6) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1), one Fe(3), and one Fe(4) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Fe(3), one Fe(4), and one Fe(6) atom. In the fourth O site, O(4) is bonded to one Mg(1), one Fe(2), one Fe(5), and one Fe(6) atom to form a mixture of distorted corner and edge-sharing OMgFe3 tetrahedra. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Fe(1), one Fe(4), and one Fe(5) atom. In the sixth O site, O(6) is bonded to one Mg(1), one Fe(1), one Fe(2), and one Fe(5) atom to form a mixture of distorted corner and edge-sharing OMgFe3 trigonal pyramids. There are six inequivalent F sites. In the first F site, F(1) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(2) atom. In the second F site, F(2) is bonded in an L-shaped geometry to one Fe(4) and one Fe(5) atom. In the third F site, F(3) is bonded in an L-shaped geometry to one Fe(4) and one Fe(6) atom. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(5), and one Fe(6) atom. In the fifth F site, F(5) is bonded in a water-like geometry to one Fe(1) and one Fe(3) atom. In the sixth F site, F(6) is bonded in a T-shaped geometry to one Mg(1), one Fe(2), and one Fe(3) atom.