Zn(FeO2)4 crystallizes in the monoclinic Cm space group. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and edges with two equivalent Zn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 48-52°. In the second Fe site, Fe(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and  a faceface with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 48-55°. In the third Fe site, Fe(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. In the fourth Fe site, Fe(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and  an edgeedge with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 51-55°. Zn(1) is bonded to one O(4), two equivalent O(6), and two equivalent O(7) atoms to form ZnO5 square pyramids that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Zn(1)O5 square pyramids, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-56°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(4) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(4) and two equivalent Fe(2) atoms. In the fourth O site, O(4) is bonded to one Fe(2), two equivalent Fe(1), and one Zn(1) atom to form OZnFe3 trigonal pyramids that share corners with two equivalent O(4)ZnFe3 trigonal pyramids, edges with two equivalent O(7)Zn2Fe3 square pyramids, and edges with two equivalent O(6)Zn2Fe3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Fe(4) and two equivalent Fe(1) atoms. In the sixth O site, O(6) is bonded to one Fe(3), two equivalent Fe(2), and two equivalent Zn(1) atoms to form distorted OZn2Fe3 trigonal bipyramids that share corners with two equivalent O(7)Zn2Fe3 square pyramids,  an edgeedge with one O(7)Zn2Fe3 square pyramid, edges with two equivalent O(6)Zn2Fe3 trigonal bipyramids, and edges with two equivalent O(4)ZnFe3 trigonal pyramids. In the seventh O site, O(7) is bonded to one Fe(1), two equivalent Fe(4), and two equivalent Zn(1) atoms to form OZn2Fe3 square pyramids that share corners with two equivalent O(6)Zn2Fe3 trigonal bipyramids, edges with two equivalent O(7)Zn2Fe3 square pyramids,  an edgeedge with one O(6)Zn2Fe3 trigonal bipyramid, and edges with two equivalent O(4)ZnFe3 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Fe(2) and two equivalent Fe(3) atoms.
Zn(FeO2)4 crystallizes in the monoclinic Cm space group. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(2), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form distorted FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and edges with two equivalent Zn(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 48-52°. The Fe(1)-O(2) bond length is 1.96 Å. The Fe(1)-O(7) bond length is 2.28 Å. Both Fe(1)-O(4) bond lengths are 2.00 Å. Both Fe(1)-O(5) bond lengths are 1.94 Å. In the second Fe site, Fe(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with two equivalent Fe(2)O6 octahedra, edges with two equivalent Fe(3)O6 octahedra, and  a faceface with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 48-55°. The Fe(2)-O(4) bond length is 2.00 Å. The Fe(2)-O(8) bond length is 1.95 Å. Both Fe(2)-O(3) bond lengths are 1.91 Å. Both Fe(2)-O(6) bond lengths are 2.26 Å. In the third Fe site, Fe(3) is bonded to one O(1), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with two equivalent Fe(2)O6 octahedra, and edges with two equivalent Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-52°. The Fe(3)-O(1) bond length is 2.00 Å. The Fe(3)-O(6) bond length is 2.10 Å. Both Fe(3)-O(2) bond lengths are 1.96 Å. Both Fe(3)-O(8) bond lengths are 1.98 Å. In the fourth Fe site, Fe(4) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(7) atoms to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Zn(1)O5 square pyramids, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Fe(4)O6 octahedra, and  an edgeedge with one Zn(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 51-55°. The Fe(4)-O(3) bond length is 2.00 Å. The Fe(4)-O(5) bond length is 2.05 Å. Both Fe(4)-O(1) bond lengths are 1.93 Å. Both Fe(4)-O(7) bond lengths are 2.16 Å. Zn(1) is bonded to one O(4), two equivalent O(6), and two equivalent O(7) atoms to form ZnO5 square pyramids that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Fe(3)O6 octahedra, corners with two equivalent Fe(4)O6 octahedra,  an edgeedge with one Fe(4)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Zn(1)O5 square pyramids, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-56°. The Zn(1)-O(4) bond length is 2.19 Å. Both Zn(1)-O(6) bond lengths are 2.07 Å. Both Zn(1)-O(7) bond lengths are 2.07 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Fe(3) and two equivalent Fe(4) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(1) and two equivalent Fe(3) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Fe(4) and two equivalent Fe(2) atoms. In the fourth O site, O(4) is bonded to one Fe(2), two equivalent Fe(1), and one Zn(1) atom to form OZnFe3 trigonal pyramids that share corners with two equivalent O(4)ZnFe3 trigonal pyramids, edges with two equivalent O(7)Zn2Fe3 square pyramids, and edges with two equivalent O(6)Zn2Fe3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Fe(4) and two equivalent Fe(1) atoms. In the sixth O site, O(6) is bonded to one Fe(3), two equivalent Fe(2), and two equivalent Zn(1) atoms to form distorted OZn2Fe3 trigonal bipyramids that share corners with two equivalent O(7)Zn2Fe3 square pyramids,  an edgeedge with one O(7)Zn2Fe3 square pyramid, edges with two equivalent O(6)Zn2Fe3 trigonal bipyramids, and edges with two equivalent O(4)ZnFe3 trigonal pyramids. In the seventh O site, O(7) is bonded to one Fe(1), two equivalent Fe(4), and two equivalent Zn(1) atoms to form OZn2Fe3 square pyramids that share corners with two equivalent O(6)Zn2Fe3 trigonal bipyramids, edges with two equivalent O(7)Zn2Fe3 square pyramids,  an edgeedge with one O(6)Zn2Fe3 trigonal bipyramid, and edges with two equivalent O(4)ZnFe3 trigonal pyramids. In the eighth O site, O(8) is bonded in a trigonal non-coplanar geometry to one Fe(2) and two equivalent Fe(3) atoms.