Na3SnSi3O9F crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to four equivalent O(4) and two equivalent F(1) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one F(1) atom. Sn(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SnO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with two equivalent Sn(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-47°. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Sn(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(2), one Sn(1), and one Si(1) atom. In the second O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Sn(1), and one Si(1) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(2), one Sn(1), and one Si(2) atom. In the fifth O site, O(2) is bonded in a distorted trigonal planar geometry to one Na(2), one Si(1), and one Si(2) atom. F(1) is bonded to two equivalent Na(1) and two equivalent Na(2) atoms to form edge-sharing FNa4 tetrahedra.
Na3SnSi3O9F crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to four equivalent O(4) and two equivalent F(1) atoms. There are two shorter (2.37 Å) and two longer (2.85 Å) Na(1)-O(4) bond lengths. There is one shorter (2.20 Å) and one longer (2.25 Å) Na(1)-F(1) bond length. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(3), and one F(1) atom. The Na(2)-O(1) bond length is 2.37 Å. The Na(2)-O(2) bond length is 2.32 Å. The Na(2)-O(3) bond length is 2.30 Å. The Na(2)-F(1) bond length is 2.12 Å. Sn(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form SnO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra and corners with four equivalent Si(1)O4 tetrahedra. Both Sn(1)-O(1) bond lengths are 2.07 Å. Both Sn(1)-O(3) bond lengths are 2.05 Å. Both Sn(1)-O(4) bond lengths are 2.05 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share corners with two equivalent Sn(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-47°. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(3) bond length is 1.61 Å. The Si(1)-O(4) bond length is 1.61 Å. The Si(1)-O(5) bond length is 1.62 Å. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Sn(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. Both Si(2)-O(1) bond lengths are 1.61 Å. Both Si(2)-O(2) bond lengths are 1.64 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(2), one Sn(1), and one Si(1) atom. In the second O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(1), one Sn(1), and one Si(1) atom. In the third O site, O(5) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(2), one Sn(1), and one Si(2) atom. In the fifth O site, O(2) is bonded in a distorted trigonal planar geometry to one Na(2), one Si(1), and one Si(2) atom. F(1) is bonded to two equivalent Na(1) and two equivalent Na(2) atoms to form edge-sharing FNa4 tetrahedra.