FeZn(GeO3)2 crystallizes in the monoclinic P2_1/c space group. Fe(1) is bonded to one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with three equivalent Ge(1)O4 tetrahedra, corners with three equivalent Ge(2)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Zn(1)O6 octahedra. Zn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted ZnO6 octahedra that share corners with two equivalent Ge(2)O4 tetrahedra, corners with four equivalent Ge(1)O4 tetrahedra, edges with three equivalent Fe(1)O6 octahedra, and  an edgeedge with one Ge(2)O4 tetrahedra. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(4), one O(5), and two equivalent O(2) atoms to form GeO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with four equivalent Zn(1)O6 octahedra, and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-69°. In the second Ge site, Ge(2) is bonded to one O(3), one O(6), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with two equivalent Zn(1)O6 octahedra, corners with three equivalent Fe(1)O6 octahedra, corners with two equivalent Ge(2)O4 tetrahedra, and  an edgeedge with one Zn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-60°. There are six inequivalent O sites. In the first O site, O(5) is bonded to two equivalent Fe(1), one Zn(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OZnFe2Ge trigonal pyramids. In the second O site, O(6) is bonded to two equivalent Fe(1), one Zn(1), and one Ge(2) atom to form a mixture of distorted corner and edge-sharing OZnFe2Ge trigonal pyramids. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Zn(1) and two equivalent Ge(2) atoms. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to one Zn(1) and two equivalent Ge(1) atoms. In the fifth O site, O(3) is bonded in a T-shaped geometry to one Fe(1), one Zn(1), and one Ge(2) atom. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one Ge(1) atom.
FeZn(GeO3)2 crystallizes in the monoclinic P2_1/c space group. Fe(1) is bonded to one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with three equivalent Ge(1)O4 tetrahedra, corners with three equivalent Ge(2)O4 tetrahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Zn(1)O6 octahedra. The Fe(1)-O(3) bond length is 2.10 Å. The Fe(1)-O(4) bond length is 2.14 Å. There is one shorter (2.17 Å) and one longer (2.21 Å) Fe(1)-O(5) bond length. There is one shorter (2.11 Å) and one longer (2.25 Å) Fe(1)-O(6) bond length. Zn(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted ZnO6 octahedra that share corners with two equivalent Ge(2)O4 tetrahedra, corners with four equivalent Ge(1)O4 tetrahedra, edges with three equivalent Fe(1)O6 octahedra, and  an edgeedge with one Ge(2)O4 tetrahedra. The Zn(1)-O(1) bond length is 2.37 Å. The Zn(1)-O(2) bond length is 2.52 Å. The Zn(1)-O(3) bond length is 2.07 Å. The Zn(1)-O(4) bond length is 2.01 Å. The Zn(1)-O(5) bond length is 2.11 Å. The Zn(1)-O(6) bond length is 2.14 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(4), one O(5), and two equivalent O(2) atoms to form GeO4 tetrahedra that share corners with three equivalent Fe(1)O6 octahedra, corners with four equivalent Zn(1)O6 octahedra, and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 53-69°. The Ge(1)-O(4) bond length is 1.74 Å. The Ge(1)-O(5) bond length is 1.78 Å. Both Ge(1)-O(2) bond lengths are 1.82 Å. In the second Ge site, Ge(2) is bonded to one O(3), one O(6), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with two equivalent Zn(1)O6 octahedra, corners with three equivalent Fe(1)O6 octahedra, corners with two equivalent Ge(2)O4 tetrahedra, and  an edgeedge with one Zn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 33-60°. The Ge(2)-O(3) bond length is 1.75 Å. The Ge(2)-O(6) bond length is 1.76 Å. There is one shorter (1.79 Å) and one longer (1.80 Å) Ge(2)-O(1) bond length. There are six inequivalent O sites. In the first O site, O(5) is bonded to two equivalent Fe(1), one Zn(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OZnFe2Ge trigonal pyramids. In the second O site, O(6) is bonded to two equivalent Fe(1), one Zn(1), and one Ge(2) atom to form a mixture of distorted corner and edge-sharing OZnFe2Ge trigonal pyramids. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Zn(1) and two equivalent Ge(2) atoms. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to one Zn(1) and two equivalent Ge(1) atoms. In the fifth O site, O(3) is bonded in a T-shaped geometry to one Fe(1), one Zn(1), and one Ge(2) atom. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Fe(1), one Zn(1), and one Ge(1) atom.