Zn3Si4(WO7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form WO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent W(2)O6 octahedra. In the second W site, W(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form WO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent W(1)O6 octahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), and two equivalent O(7) atoms. In the second Zn site, Zn(2) is bonded in a distorted L-shaped geometry to two equivalent O(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one W(1)O6 octahedra,  a cornercorner with one W(2)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-50°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one W(1)O6 octahedra,  a cornercorner with one W(2)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-57°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(2), one Zn(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one W(1), one W(2), and one Zn(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one W(1), one Zn(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one W(1), one W(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one Si(1) atom.
Zn3Si4(WO7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent W sites. In the first W site, W(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form WO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent W(2)O6 octahedra. Both W(1)-O(2) bond lengths are 2.05 Å. Both W(1)-O(3) bond lengths are 2.06 Å. Both W(1)-O(4) bond lengths are 2.17 Å. In the second W site, W(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form WO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent W(1)O6 octahedra. Both W(2)-O(1) bond lengths are 2.06 Å. Both W(2)-O(2) bond lengths are 2.06 Å. Both W(2)-O(4) bond lengths are 2.13 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted see-saw-like geometry to one O(1), one O(2), and two equivalent O(7) atoms. The Zn(1)-O(1) bond length is 2.19 Å. The Zn(1)-O(2) bond length is 2.02 Å. There is one shorter (2.01 Å) and one longer (2.12 Å) Zn(1)-O(7) bond length. In the second Zn site, Zn(2) is bonded in a distorted L-shaped geometry to two equivalent O(3) atoms. Both Zn(2)-O(3) bond lengths are 2.42 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one W(1)O6 octahedra,  a cornercorner with one W(2)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-50°. The Si(1)-O(4) bond length is 1.66 Å. The Si(1)-O(5) bond length is 1.64 Å. The Si(1)-O(6) bond length is 1.65 Å. The Si(1)-O(7) bond length is 1.63 Å. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one W(1)O6 octahedra,  a cornercorner with one W(2)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 54-57°. The Si(2)-O(1) bond length is 1.66 Å. The Si(2)-O(3) bond length is 1.64 Å. The Si(2)-O(5) bond length is 1.64 Å. The Si(2)-O(6) bond length is 1.65 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one W(2), one Zn(1), and one Si(2) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one W(1), one W(2), and one Zn(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one W(1), one Zn(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one W(1), one W(2), and one Si(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Si(1) and one Si(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one Si(1) atom.