MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one F(1), one F(2), one F(3), and one F(4) atom to form distorted MgOF4 trigonal bipyramids that share corners with two equivalent Fe(4)O3F2 trigonal bipyramids and corners with three equivalent Fe(1)O3F2 trigonal bipyramids. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one F(1), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share corners with three equivalent Mg(1)OF4 trigonal bipyramids and corners with three equivalent Fe(4)O3F2 trigonal bipyramids. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one F(2), and one F(3) atom. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one F(3) atom. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(3), one O(4), one F(2), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)OF4 trigonal bipyramids and corners with three equivalent Fe(1)O3F2 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form a mixture of distorted edge and corner-sharing OFe4 tetrahedra. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), one Fe(2), and one Fe(3) atom to form a mixture of distorted edge and corner-sharing OMgFe3 trigonal pyramids. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one Fe(4) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one Fe(1) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(4) atom. In the third F site, F(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(3) atom. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(4) atom.
MgFe4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(2), one F(1), one F(2), one F(3), and one F(4) atom to form distorted MgOF4 trigonal bipyramids that share corners with two equivalent Fe(4)O3F2 trigonal bipyramids and corners with three equivalent Fe(1)O3F2 trigonal bipyramids. The Mg(1)-O(2) bond length is 2.03 Å. The Mg(1)-F(1) bond length is 1.91 Å. The Mg(1)-F(2) bond length is 1.94 Å. The Mg(1)-F(3) bond length is 2.02 Å. The Mg(1)-F(4) bond length is 1.94 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(2), one O(3), one F(1), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share corners with three equivalent Mg(1)OF4 trigonal bipyramids and corners with three equivalent Fe(4)O3F2 trigonal bipyramids. The Fe(1)-O(1) bond length is 1.97 Å. The Fe(1)-O(2) bond length is 2.02 Å. The Fe(1)-O(3) bond length is 1.93 Å. The Fe(1)-F(1) bond length is 2.09 Å. The Fe(1)-F(4) bond length is 2.03 Å. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one F(2), and one F(3) atom. The Fe(2)-O(1) bond length is 2.30 Å. The Fe(2)-O(2) bond length is 2.21 Å. The Fe(2)-O(3) bond length is 2.32 Å. The Fe(2)-O(4) bond length is 2.09 Å. The Fe(2)-F(2) bond length is 2.23 Å. The Fe(2)-F(3) bond length is 2.18 Å. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one F(3) atom. The Fe(3)-O(1) bond length is 1.99 Å. The Fe(3)-O(2) bond length is 2.08 Å. The Fe(3)-O(3) bond length is 2.04 Å. The Fe(3)-O(4) bond length is 1.87 Å. The Fe(3)-F(3) bond length is 2.11 Å. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(3), one O(4), one F(2), and one F(4) atom to form distorted FeO3F2 trigonal bipyramids that share corners with two equivalent Mg(1)OF4 trigonal bipyramids and corners with three equivalent Fe(1)O3F2 trigonal bipyramids. The Fe(4)-O(1) bond length is 2.00 Å. The Fe(4)-O(3) bond length is 2.04 Å. The Fe(4)-O(4) bond length is 1.96 Å. The Fe(4)-F(2) bond length is 2.20 Å. The Fe(4)-F(4) bond length is 2.27 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom to form a mixture of distorted edge and corner-sharing OFe4 tetrahedra. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), one Fe(2), and one Fe(3) atom to form a mixture of distorted edge and corner-sharing OMgFe3 trigonal pyramids. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Fe(2), one Fe(3), and one Fe(4) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one Fe(1) atom. In the second F site, F(2) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(4) atom. In the third F site, F(3) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(2), and one Fe(3) atom. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1), one Fe(1), and one Fe(4) atom.