Fe3Zn2O8 crystallizes in the hexagonal P6_3mc space group. Fe(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with two equivalent Zn(1)O6 octahedra, corners with three equivalent Zn(2)O4 tetrahedra,  an edgeedge with one Zn(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form ZnO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, corners with three equivalent Zn(2)O4 tetrahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. In the second Zn site, Zn(2) is bonded to one O(4) and three equivalent O(2) atoms to form ZnO4 tetrahedra that share corners with three equivalent Zn(1)O6 octahedra and corners with nine equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 59-63°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one Zn(1) atom. In the second O site, O(2) is bonded to two equivalent Fe(1), one Zn(1), and one Zn(2) atom to form distorted OZn2Fe2 tetrahedra that share corners with two equivalent O(2)Zn2Fe2 tetrahedra,  a cornercorner with one O(4)ZnFe3 trigonal pyramid, edges with two equivalent O(2)Zn2Fe2 tetrahedra, and  an edgeedge with one O(4)ZnFe3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted T-shaped geometry to three equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Fe(1) and one Zn(2) atom to form a mixture of distorted edge and corner-sharing OZnFe3 trigonal pyramids.
Fe3Zn2O8 crystallizes in the hexagonal P6_3mc space group. Fe(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share corners with two equivalent Zn(1)O6 octahedra, corners with three equivalent Zn(2)O4 tetrahedra,  an edgeedge with one Zn(1)O6 octahedra, and edges with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. The Fe(1)-O(3) bond length is 1.98 Å. The Fe(1)-O(4) bond length is 2.03 Å. Both Fe(1)-O(1) bond lengths are 1.94 Å. Both Fe(1)-O(2) bond lengths are 2.02 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form ZnO6 octahedra that share corners with six equivalent Fe(1)O6 octahedra, corners with three equivalent Zn(2)O4 tetrahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Zn(1)-O(1) bond lengths are 2.04 Å. All Zn(1)-O(2) bond lengths are 2.15 Å. In the second Zn site, Zn(2) is bonded to one O(4) and three equivalent O(2) atoms to form ZnO4 tetrahedra that share corners with three equivalent Zn(1)O6 octahedra and corners with nine equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 59-63°. The Zn(2)-O(4) bond length is 2.00 Å. All Zn(2)-O(2) bond lengths are 1.97 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Fe(1) and one Zn(1) atom. In the second O site, O(2) is bonded to two equivalent Fe(1), one Zn(1), and one Zn(2) atom to form distorted OZn2Fe2 tetrahedra that share corners with two equivalent O(2)Zn2Fe2 tetrahedra,  a cornercorner with one O(4)ZnFe3 trigonal pyramid, edges with two equivalent O(2)Zn2Fe2 tetrahedra, and  an edgeedge with one O(4)ZnFe3 trigonal pyramid. In the third O site, O(3) is bonded in a distorted T-shaped geometry to three equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Fe(1) and one Zn(2) atom to form a mixture of distorted edge and corner-sharing OZnFe3 trigonal pyramids.