MgMn2(FeO2)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(1), one O(5), one O(6), and one O(8) atom. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form distorted MnO4 tetrahedra that share corners with three equivalent Fe(1)O5 square pyramids, corners with three equivalent Fe(2)O5 trigonal bipyramids, and corners with three equivalent Fe(4)O5 trigonal bipyramids. In the second Mn site, Mn(2) is bonded to one O(1), one O(5), one O(6), and one O(8) atom to form MnO4 tetrahedra that share corners with two equivalent Fe(1)O5 square pyramids, corners with two equivalent Fe(2)O5 trigonal bipyramids, and corners with two equivalent Fe(4)O5 trigonal bipyramids. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted FeO5 square pyramids that share corners with two equivalent Mn(2)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra,  an edgeedge with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(4)O5 trigonal bipyramid. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Mn(2)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra,  an edgeedge with one Fe(1)O5 square pyramid, and edges with two equivalent Fe(4)O5 trigonal bipyramids. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), one O(7), and one O(8) atom. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Mn(2)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra,  an edgeedge with one Fe(1)O5 square pyramid, and edges with two equivalent Fe(2)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mn(2), one Fe(2), and one Fe(4) atom to form distorted corner-sharing OMgMnFe2 tetrahedra. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Fe(1), one Fe(3), and one Fe(4) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Fe(1), one Fe(2), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Fe(1), one Fe(2), and one Fe(4) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Mn(2), one Fe(1), and one Fe(3) atom to form a mixture of distorted face and corner-sharing OMgMnFe2 tetrahedra. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(1), one Mn(2), one Fe(2), and one Fe(4) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the eighth O site, O(8) is bonded to one Mg(1), one Mn(2), one Fe(1), and one Fe(3) atom to form a mixture of distorted face and corner-sharing OMgMnFe2 tetrahedra.
MgMn2(FeO2)4 crystallizes in the triclinic P1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(1), one O(5), one O(6), and one O(8) atom. The Mg(1)-O(1) bond length is 1.91 Å. The Mg(1)-O(5) bond length is 2.00 Å. The Mg(1)-O(6) bond length is 2.04 Å. The Mg(1)-O(8) bond length is 2.00 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(4), and one O(7) atom to form distorted MnO4 tetrahedra that share corners with three equivalent Fe(1)O5 square pyramids, corners with three equivalent Fe(2)O5 trigonal bipyramids, and corners with three equivalent Fe(4)O5 trigonal bipyramids. The Mn(1)-O(2) bond length is 2.22 Å. The Mn(1)-O(3) bond length is 2.23 Å. The Mn(1)-O(4) bond length is 2.44 Å. The Mn(1)-O(7) bond length is 2.14 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(5), one O(6), and one O(8) atom to form MnO4 tetrahedra that share corners with two equivalent Fe(1)O5 square pyramids, corners with two equivalent Fe(2)O5 trigonal bipyramids, and corners with two equivalent Fe(4)O5 trigonal bipyramids. The Mn(2)-O(1) bond length is 2.02 Å. The Mn(2)-O(5) bond length is 2.20 Å. The Mn(2)-O(6) bond length is 2.17 Å. The Mn(2)-O(8) bond length is 2.19 Å. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted FeO5 square pyramids that share corners with two equivalent Mn(2)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra,  an edgeedge with one Fe(2)O5 trigonal bipyramid, and  an edgeedge with one Fe(4)O5 trigonal bipyramid. The Fe(1)-O(2) bond length is 2.06 Å. The Fe(1)-O(3) bond length is 2.04 Å. The Fe(1)-O(4) bond length is 1.95 Å. The Fe(1)-O(5) bond length is 2.04 Å. The Fe(1)-O(8) bond length is 2.04 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(3), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Mn(2)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra,  an edgeedge with one Fe(1)O5 square pyramid, and edges with two equivalent Fe(4)O5 trigonal bipyramids. The Fe(2)-O(1) bond length is 2.15 Å. The Fe(2)-O(3) bond length is 2.14 Å. The Fe(2)-O(4) bond length is 2.06 Å. The Fe(2)-O(6) bond length is 2.02 Å. The Fe(2)-O(7) bond length is 2.11 Å. In the third Fe site, Fe(3) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(5), one O(7), and one O(8) atom. The Fe(3)-O(2) bond length is 2.07 Å. The Fe(3)-O(3) bond length is 2.07 Å. The Fe(3)-O(5) bond length is 2.06 Å. The Fe(3)-O(7) bond length is 1.94 Å. The Fe(3)-O(8) bond length is 2.06 Å. In the fourth Fe site, Fe(4) is bonded to one O(1), one O(2), one O(4), one O(6), and one O(7) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Mn(2)O4 tetrahedra, corners with three equivalent Mn(1)O4 tetrahedra,  an edgeedge with one Fe(1)O5 square pyramid, and edges with two equivalent Fe(2)O5 trigonal bipyramids. The Fe(4)-O(1) bond length is 2.14 Å. The Fe(4)-O(2) bond length is 2.11 Å. The Fe(4)-O(4) bond length is 2.07 Å. The Fe(4)-O(6) bond length is 2.02 Å. The Fe(4)-O(7) bond length is 2.12 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Mn(2), one Fe(2), and one Fe(4) atom to form distorted corner-sharing OMgMnFe2 tetrahedra. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Fe(1), one Fe(3), and one Fe(4) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Fe(1), one Fe(2), and one Fe(3) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mn(1), one Fe(1), one Fe(2), and one Fe(4) atom. In the fifth O site, O(5) is bonded to one Mg(1), one Mn(2), one Fe(1), and one Fe(3) atom to form a mixture of distorted face and corner-sharing OMgMnFe2 tetrahedra. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one Mg(1), one Mn(2), one Fe(2), and one Fe(4) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the eighth O site, O(8) is bonded to one Mg(1), one Mn(2), one Fe(1), and one Fe(3) atom to form a mixture of distorted face and corner-sharing OMgMnFe2 tetrahedra.