MgMn4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), one F(1), one F(3), and one F(4) atom to form MgO3F3 octahedra that share edges with two equivalent Mn(4)O3F3 octahedra. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one F(1), one F(2), and one F(3) atom. In the second Mn site, Mn(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one F(1), one F(3), and one F(4) atom. In the third Mn site, Mn(3) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one F(2), and one F(3) atom. In the fourth Mn site, Mn(4) is bonded to one O(2), one O(3), one O(4), one F(1), one F(2), and one F(4) atom to form MnO3F3 octahedra that share edges with two equivalent Mg(1)O3F3 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form distorted OMgMn3 tetrahedra that share corners with two equivalent F(3)MgMn3 trigonal pyramids and  an edgeedge with one F(3)MgMn3 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Mn(4) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Mg(1), one Mn(2), one Mn(3), and one Mn(4) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mn(1), one Mn(3), and one Mn(4) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Mn(4) atom. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Mn(1), one Mn(3), and one Mn(4) atom. In the third F site, F(3) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form distorted FMgMn3 trigonal pyramids that share corners with two equivalent O(1)MgMn3 tetrahedra and  an edgeedge with one O(1)MgMn3 tetrahedra. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1), one Mn(2), and one Mn(4) atom.
MgMn4(OF)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), one F(1), one F(3), and one F(4) atom to form MgO3F3 octahedra that share edges with two equivalent Mn(4)O3F3 octahedra. The Mg(1)-O(1) bond length is 2.02 Å. The Mg(1)-O(2) bond length is 2.20 Å. The Mg(1)-O(3) bond length is 2.09 Å. The Mg(1)-F(1) bond length is 1.99 Å. The Mg(1)-F(3) bond length is 2.11 Å. The Mg(1)-F(4) bond length is 1.99 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one F(1), one F(2), and one F(3) atom. The Mn(1)-O(1) bond length is 2.14 Å. The Mn(1)-O(2) bond length is 2.15 Å. The Mn(1)-O(4) bond length is 2.07 Å. The Mn(1)-F(1) bond length is 2.68 Å. The Mn(1)-F(2) bond length is 2.17 Å. The Mn(1)-F(3) bond length is 2.37 Å. In the second Mn site, Mn(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one F(1), one F(3), and one F(4) atom. The Mn(2)-O(1) bond length is 1.87 Å. The Mn(2)-O(2) bond length is 1.94 Å. The Mn(2)-O(3) bond length is 1.94 Å. The Mn(2)-F(1) bond length is 2.55 Å. The Mn(2)-F(3) bond length is 2.00 Å. The Mn(2)-F(4) bond length is 2.27 Å. In the third Mn site, Mn(3) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(4), one F(2), and one F(3) atom. The Mn(3)-O(1) bond length is 2.20 Å. The Mn(3)-O(3) bond length is 2.15 Å. The Mn(3)-O(4) bond length is 2.04 Å. The Mn(3)-F(2) bond length is 2.25 Å. The Mn(3)-F(3) bond length is 2.27 Å. In the fourth Mn site, Mn(4) is bonded to one O(2), one O(3), one O(4), one F(1), one F(2), and one F(4) atom to form MnO3F3 octahedra that share edges with two equivalent Mg(1)O3F3 octahedra. The Mn(4)-O(2) bond length is 2.01 Å. The Mn(4)-O(3) bond length is 1.98 Å. The Mn(4)-O(4) bond length is 1.89 Å. The Mn(4)-F(1) bond length is 2.20 Å. The Mn(4)-F(2) bond length is 2.08 Å. The Mn(4)-F(4) bond length is 2.24 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form distorted OMgMn3 tetrahedra that share corners with two equivalent F(3)MgMn3 trigonal pyramids and  an edgeedge with one F(3)MgMn3 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Mn(4) atom. In the third O site, O(3) is bonded in a distorted see-saw-like geometry to one Mg(1), one Mn(2), one Mn(3), and one Mn(4) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mn(1), one Mn(3), and one Mn(4) atom. There are four inequivalent F sites. In the first F site, F(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mn(1), one Mn(2), and one Mn(4) atom. In the second F site, F(2) is bonded in a distorted T-shaped geometry to one Mn(1), one Mn(3), and one Mn(4) atom. In the third F site, F(3) is bonded to one Mg(1), one Mn(1), one Mn(2), and one Mn(3) atom to form distorted FMgMn3 trigonal pyramids that share corners with two equivalent O(1)MgMn3 tetrahedra and  an edgeedge with one O(1)MgMn3 tetrahedra. In the fourth F site, F(4) is bonded in a 3-coordinate geometry to one Mg(1), one Mn(2), and one Mn(4) atom.