Zn3Sn2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted ZnO4 tetrahedra that share corners with eight equivalent Sn(1)O6 octahedra and corners with two equivalent Zn(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 64-83°. In the second Zn site, Zn(2) is bonded to one O(2) and three equivalent O(1) atoms to form distorted ZnO4 tetrahedra that share corners with five equivalent Sn(1)O6 octahedra and corners with six equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-82°. Sn(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form SnO6 octahedra that share corners with five equivalent Sn(1)O6 octahedra, corners with four equivalent Zn(1)O4 tetrahedra, and corners with five equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-49°. There are four inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Zn(2) and one Sn(1) atom to form OZn3Sn tetrahedra that share  a cornercorner with one O(4)Zn2Sn2 tetrahedra and corners with six equivalent O(1)Zn3Sn tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to one Zn(2) and two equivalent Sn(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Zn(1) and two equivalent Sn(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Zn(1) and two equivalent Sn(1) atoms to form distorted OZn2Sn2 tetrahedra that share corners with two equivalent O(4)Zn2Sn2 tetrahedra and corners with two equivalent O(1)Zn3Sn tetrahedra.
Zn3Sn2O7 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form distorted ZnO4 tetrahedra that share corners with eight equivalent Sn(1)O6 octahedra and corners with two equivalent Zn(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 64-83°. Both Zn(1)-O(3) bond lengths are 2.02 Å. There is one shorter (2.09 Å) and one longer (2.14 Å) Zn(1)-O(4) bond length. In the second Zn site, Zn(2) is bonded to one O(2) and three equivalent O(1) atoms to form distorted ZnO4 tetrahedra that share corners with five equivalent Sn(1)O6 octahedra and corners with six equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-82°. The Zn(2)-O(2) bond length is 2.03 Å. There are a spread of Zn(2)-O(1) bond distances ranging from 2.02-2.07 Å. Sn(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form SnO6 octahedra that share corners with five equivalent Sn(1)O6 octahedra, corners with four equivalent Zn(1)O4 tetrahedra, and corners with five equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-49°. The Sn(1)-O(1) bond length is 2.11 Å. The Sn(1)-O(4) bond length is 2.16 Å. There is one shorter (2.06 Å) and one longer (2.11 Å) Sn(1)-O(2) bond length. There is one shorter (2.07 Å) and one longer (2.12 Å) Sn(1)-O(3) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Zn(2) and one Sn(1) atom to form OZn3Sn tetrahedra that share  a cornercorner with one O(4)Zn2Sn2 tetrahedra and corners with six equivalent O(1)Zn3Sn tetrahedra. In the second O site, O(2) is bonded in a trigonal planar geometry to one Zn(2) and two equivalent Sn(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Zn(1) and two equivalent Sn(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Zn(1) and two equivalent Sn(1) atoms to form distorted OZn2Sn2 tetrahedra that share corners with two equivalent O(4)Zn2Sn2 tetrahedra and corners with two equivalent O(1)Zn3Sn tetrahedra.