MgZn2(FeO2)4 crystallizes in the trigonal R3m space group. Mg(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Zn(2)O6 octahedra and edges with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2) and three equivalent O(1) atoms. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3) and three equivalent O(4) atoms. In the second Zn site, Zn(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), two equivalent Fe(2), and one Zn(2) atom to form OMgZnFe3 square pyramids that share corners with six equivalent O(4)MgZn2Fe2 square pyramids, corners with two equivalent O(3)ZnFe3 tetrahedra,  a cornercorner with one O(2)Fe4 trigonal pyramid, edges with two equivalent O(4)MgZn2Fe2 square pyramids, edges with four equivalent O(1)MgZnFe3 square pyramids, and  an edgeedge with one O(2)Fe4 trigonal pyramid. In the second O site, O(2) is bonded to one Fe(1) and three equivalent Fe(2) atoms to form distorted OFe4 trigonal pyramids that share corners with three equivalent O(1)MgZnFe3 square pyramids, corners with six equivalent O(4)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra, and edges with three equivalent O(1)MgZnFe3 square pyramids. In the third O site, O(3) is bonded to three equivalent Fe(2) and one Zn(1) atom to form distorted OZnFe3 tetrahedra that share corners with three equivalent O(4)MgZn2Fe2 square pyramids, corners with six equivalent O(1)MgZnFe3 square pyramids, corners with three equivalent O(2)Fe4 trigonal pyramids, and edges with three equivalent O(4)MgZn2Fe2 square pyramids. In the fourth O site, O(4) is bonded to one Mg(1), two equivalent Fe(2), one Zn(1), and one Zn(2) atom to form OMgZn2Fe2 square pyramids that share corners with six equivalent O(1)MgZnFe3 square pyramids,  a cornercorner with one O(3)ZnFe3 tetrahedra, corners with two equivalent O(2)Fe4 trigonal pyramids, edges with two equivalent O(1)MgZnFe3 square pyramids, edges with four equivalent O(4)MgZn2Fe2 square pyramids, and  an edgeedge with one O(3)ZnFe3 tetrahedra.
MgZn2(FeO2)4 crystallizes in the trigonal R3m space group. Mg(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form MgO6 octahedra that share corners with six equivalent Zn(2)O6 octahedra and edges with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. All Mg(1)-O(1) bond lengths are 2.18 Å. All Mg(1)-O(4) bond lengths are 2.08 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a distorted rectangular see-saw-like geometry to one O(2) and three equivalent O(1) atoms. The Fe(1)-O(2) bond length is 1.84 Å. All Fe(1)-O(1) bond lengths are 1.99 Å. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms to form FeO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Zn(2)O6 octahedra, and edges with four equivalent Fe(2)O6 octahedra. The Fe(2)-O(2) bond length is 2.04 Å. The Fe(2)-O(3) bond length is 2.00 Å. Both Fe(2)-O(1) bond lengths are 2.19 Å. Both Fe(2)-O(4) bond lengths are 2.15 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted rectangular see-saw-like geometry to one O(3) and three equivalent O(4) atoms. The Zn(1)-O(3) bond length is 1.84 Å. All Zn(1)-O(4) bond lengths are 2.10 Å. In the second Zn site, Zn(2) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form ZnO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra and edges with six equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. All Zn(2)-O(1) bond lengths are 2.29 Å. All Zn(2)-O(4) bond lengths are 2.17 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Fe(1), two equivalent Fe(2), and one Zn(2) atom to form OMgZnFe3 square pyramids that share corners with six equivalent O(4)MgZn2Fe2 square pyramids, corners with two equivalent O(3)ZnFe3 tetrahedra,  a cornercorner with one O(2)Fe4 trigonal pyramid, edges with two equivalent O(4)MgZn2Fe2 square pyramids, edges with four equivalent O(1)MgZnFe3 square pyramids, and  an edgeedge with one O(2)Fe4 trigonal pyramid. In the second O site, O(2) is bonded to one Fe(1) and three equivalent Fe(2) atoms to form distorted OFe4 trigonal pyramids that share corners with three equivalent O(1)MgZnFe3 square pyramids, corners with six equivalent O(4)MgZn2Fe2 square pyramids, corners with three equivalent O(3)ZnFe3 tetrahedra, and edges with three equivalent O(1)MgZnFe3 square pyramids. In the third O site, O(3) is bonded to three equivalent Fe(2) and one Zn(1) atom to form distorted OZnFe3 tetrahedra that share corners with three equivalent O(4)MgZn2Fe2 square pyramids, corners with six equivalent O(1)MgZnFe3 square pyramids, corners with three equivalent O(2)Fe4 trigonal pyramids, and edges with three equivalent O(4)MgZn2Fe2 square pyramids. In the fourth O site, O(4) is bonded to one Mg(1), two equivalent Fe(2), one Zn(1), and one Zn(2) atom to form OMgZn2Fe2 square pyramids that share corners with six equivalent O(1)MgZnFe3 square pyramids,  a cornercorner with one O(3)ZnFe3 tetrahedra, corners with two equivalent O(2)Fe4 trigonal pyramids, edges with two equivalent O(1)MgZnFe3 square pyramids, edges with four equivalent O(4)MgZn2Fe2 square pyramids, and  an edgeedge with one O(3)ZnFe3 tetrahedra.