MgZn2(FeO2)4 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Zn(1)O6 octahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-5°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), and two equivalent O(1) atoms. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Zn(1)O6 octahedra, and edges with two equivalent Zn(2)O6 octahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form ZnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-5°. In the second Zn site, Zn(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form ZnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Zn(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), one Fe(2), one Zn(1), and one Zn(2) atom to form OMgZn2Fe2 square pyramids that share corners with five equivalent O(1)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra,  a cornercorner with one O(2)MgZnFe3 trigonal bipyramid, edges with three equivalent O(1)MgZn2Fe2 square pyramids,  an edgeedge with one O(3)ZnFe3 tetrahedra, and edges with three equivalent O(2)MgZnFe3 trigonal bipyramids. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), two equivalent Fe(2), and one Zn(1) atom to form OMgZnFe3 trigonal bipyramids that share corners with two equivalent O(1)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra, corners with four equivalent O(2)MgZnFe3 trigonal bipyramids, edges with six equivalent O(1)MgZn2Fe2 square pyramids, and  an edgeedge with one O(3)ZnFe3 tetrahedra. In the third O site, O(3) is bonded to one Fe(1), two equivalent Fe(2), and one Zn(2) atom to form distorted OZnFe3 tetrahedra that share corners with six equivalent O(1)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra, corners with three equivalent O(2)MgZnFe3 trigonal bipyramids, edges with two equivalent O(1)MgZn2Fe2 square pyramids, and  an edgeedge with one O(2)MgZnFe3 trigonal bipyramid.
MgZn2(FeO2)4 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Zn(1)O6 octahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-5°. Both Mg(1)-O(2) bond lengths are 2.09 Å. All Mg(1)-O(1) bond lengths are 2.14 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a rectangular see-saw-like geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Fe(1)-O(2) bond length is 2.15 Å. The Fe(1)-O(3) bond length is 1.91 Å. Both Fe(1)-O(1) bond lengths are 2.08 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form FeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Zn(1)O6 octahedra, and edges with two equivalent Zn(2)O6 octahedra. Both Fe(2)-O(1) bond lengths are 2.09 Å. Both Fe(2)-O(2) bond lengths are 2.13 Å. Both Fe(2)-O(3) bond lengths are 1.97 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form ZnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-5°. Both Zn(1)-O(2) bond lengths are 2.27 Å. All Zn(1)-O(1) bond lengths are 2.23 Å. In the second Zn site, Zn(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form ZnO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Zn(1)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. Both Zn(2)-O(3) bond lengths are 2.01 Å. All Zn(2)-O(1) bond lengths are 2.19 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), one Fe(2), one Zn(1), and one Zn(2) atom to form OMgZn2Fe2 square pyramids that share corners with five equivalent O(1)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra,  a cornercorner with one O(2)MgZnFe3 trigonal bipyramid, edges with three equivalent O(1)MgZn2Fe2 square pyramids,  an edgeedge with one O(3)ZnFe3 tetrahedra, and edges with three equivalent O(2)MgZnFe3 trigonal bipyramids. In the second O site, O(2) is bonded to one Mg(1), one Fe(1), two equivalent Fe(2), and one Zn(1) atom to form OMgZnFe3 trigonal bipyramids that share corners with two equivalent O(1)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra, corners with four equivalent O(2)MgZnFe3 trigonal bipyramids, edges with six equivalent O(1)MgZn2Fe2 square pyramids, and  an edgeedge with one O(3)ZnFe3 tetrahedra. In the third O site, O(3) is bonded to one Fe(1), two equivalent Fe(2), and one Zn(2) atom to form distorted OZnFe3 tetrahedra that share corners with six equivalent O(1)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra, corners with three equivalent O(2)MgZnFe3 trigonal bipyramids, edges with two equivalent O(1)MgZn2Fe2 square pyramids, and  an edgeedge with one O(2)MgZnFe3 trigonal bipyramid.