Li3BSnSiO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), 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(3), one O(4), and one O(6) atom. B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. Sn(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form SnO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with four equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), two equivalent Li(2), and one B(1) atom to form corner-sharing OLi3B tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one B(1), and one Sn(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Li(2), one B(1), and one Sn(1) atom. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Sn(1), and one Si(1) atom to form distorted OLi2SiSn trigonal pyramids that share corners with two equivalent O(1)Li3B tetrahedra,  a cornercorner with one O(4)Li2SiSn trigonal pyramid, and  an edgeedge with one O(4)Li2SiSn trigonal pyramid. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Sn(1) and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li(2), one Sn(1), and one Si(1) atom.
Li3BSnSiO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one O(1), one O(2), and two equivalent O(4) atoms. The Li(1)-O(1) bond length is 2.00 Å. The Li(1)-O(2) bond length is 1.99 Å. Both Li(1)-O(4) bond lengths are 2.27 Å. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), one O(4), and one O(6) atom. The Li(2)-O(1) bond length is 1.95 Å. The Li(2)-O(3) bond length is 2.22 Å. The Li(2)-O(4) bond length is 2.21 Å. The Li(2)-O(6) bond length is 2.26 Å. B(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The B(1)-O(1) bond length is 1.35 Å. The B(1)-O(2) bond length is 1.40 Å. The B(1)-O(3) bond length is 1.43 Å. Sn(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form SnO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra. The Sn(1)-O(2) bond length is 2.21 Å. The Sn(1)-O(3) bond length is 2.08 Å. The Sn(1)-O(5) bond length is 2.05 Å. The Sn(1)-O(6) bond length is 2.06 Å. Both Sn(1)-O(4) bond lengths are 2.06 Å. Si(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form SiO4 tetrahedra that share corners with four equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-56°. The Si(1)-O(5) bond length is 1.66 Å. The Si(1)-O(6) bond length is 1.64 Å. Both Si(1)-O(4) bond lengths are 1.64 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), two equivalent Li(2), and one B(1) atom to form corner-sharing OLi3B tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Li(1), one B(1), and one Sn(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Li(2), one B(1), and one Sn(1) atom. In the fourth O site, O(4) is bonded to one Li(1), one Li(2), one Sn(1), and one Si(1) atom to form distorted OLi2SiSn trigonal pyramids that share corners with two equivalent O(1)Li3B tetrahedra,  a cornercorner with one O(4)Li2SiSn trigonal pyramid, and  an edgeedge with one O(4)Li2SiSn trigonal pyramid. In the fifth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Sn(1) and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Li(2), one Sn(1), and one Si(1) atom.