Na3BSnSiO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), 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 40-49°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one B(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one B(1), and one Sn(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), two equivalent Na(2), one B(1), and one Sn(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Sn(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Sn(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to two equivalent Na(2), one Sn(1), and one Si(1) atom.
Na3BSnSiO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. The Na(1)-O(2) bond length is 2.36 Å. The Na(1)-O(3) bond length is 2.81 Å. There is one shorter (2.39 Å) and one longer (2.98 Å) Na(1)-O(1) bond length. Both Na(1)-O(4) bond lengths are 2.56 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Na(2)-O(1) bond length is 2.25 Å. The Na(2)-O(2) bond length is 2.62 Å. The Na(2)-O(3) bond length is 2.36 Å. The Na(2)-O(4) bond length is 2.57 Å. The Na(2)-O(5) bond length is 2.72 Å. The Na(2)-O(6) bond length is 2.40 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 1.34 Å. The B(1)-O(2) bond length is 1.41 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 2.15 Å. The Sn(1)-O(3) bond length is 2.10 Å. The Sn(1)-O(5) bond length is 2.06 Å. The Sn(1)-O(6) bond length is 2.06 Å. Both Sn(1)-O(4) bond lengths are 2.10 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 40-49°. 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 in a 4-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one B(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), two equivalent Na(2), one B(1), and one Sn(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1), two equivalent Na(2), one B(1), and one Sn(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Sn(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one Sn(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to two equivalent Na(2), one Sn(1), and one Si(1) atom.