Li2WSi2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(7), and two equivalent O(4) atoms. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(6) atom. W(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form WO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with three equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent W(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-65°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent W(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 23-52°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to one Li(1), one Li(2), one W(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(2), one W(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one W(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(2), one W(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Li(2), one W(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one W(1), and one Si(2) atom.
Li2WSi2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 5-coordinate geometry to one O(1), one O(3), one O(7), and two equivalent O(4) atoms. The Li(1)-O(1) bond length is 2.07 Å. The Li(1)-O(3) bond length is 2.04 Å. The Li(1)-O(7) bond length is 1.99 Å. There is one shorter (2.30 Å) and one longer (2.52 Å) Li(1)-O(4) bond length. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(6) atom. The Li(2)-O(1) bond length is 2.09 Å. The Li(2)-O(2) bond length is 2.13 Å. The Li(2)-O(5) bond length is 2.17 Å. The Li(2)-O(6) bond length is 2.20 Å. W(1) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and one O(7) atom to form WO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra and corners with three equivalent Si(2)O4 tetrahedra. The W(1)-O(1) bond length is 2.17 Å. The W(1)-O(2) bond length is 2.03 Å. The W(1)-O(3) bond length is 2.03 Å. The W(1)-O(5) bond length is 2.11 Å. The W(1)-O(6) bond length is 2.02 Å. The W(1)-O(7) bond length is 2.14 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with three equivalent W(1)O6 octahedra and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-65°. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.62 Å. The Si(1)-O(4) bond length is 1.68 Å. The Si(1)-O(5) bond length is 1.66 Å. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with three equivalent W(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 23-52°. The Si(2)-O(3) bond length is 1.62 Å. The Si(2)-O(4) bond length is 1.68 Å. The Si(2)-O(6) bond length is 1.62 Å. The Si(2)-O(7) bond length is 1.63 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal pyramidal geometry to one Li(1), one Li(2), one W(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(2), one W(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one Li(1), one W(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Li(1), one Si(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Li(2), one W(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Li(2), one W(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Li(1), one W(1), and one Si(2) atom.