Na3SnSiCO7 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 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. Sn(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. Si(1) is bonded in a tetrahedral geometry to one O(5), one O(6), and two equivalent O(4) atoms. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Sn(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Sn(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(2), one Sn(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted tetrahedral 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.
Na3SnSiCO7 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 2.43 Å. The Na(1)-O(3) bond length is 2.50 Å. There is one shorter (2.51 Å) and one longer (2.71 Å) Na(1)-O(1) bond length. Both Na(1)-O(4) bond lengths are 2.50 Å. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. The Na(2)-O(1) bond length is 2.34 Å. The Na(2)-O(2) bond length is 2.67 Å. The Na(2)-O(3) bond length is 2.58 Å. The Na(2)-O(5) bond length is 2.37 Å. The Na(2)-O(6) bond length is 2.40 Å. There is one shorter (2.46 Å) and one longer (2.93 Å) Na(2)-O(4) bond length. Sn(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. The Sn(1)-O(2) bond length is 2.49 Å. The Sn(1)-O(3) bond length is 2.55 Å. The Sn(1)-O(5) bond length is 2.20 Å. The Sn(1)-O(6) bond length is 2.16 Å. Both Sn(1)-O(4) bond lengths are 2.22 Å. Si(1) is bonded in a tetrahedral geometry to one O(5), one O(6), and two equivalent O(4) atoms. The Si(1)-O(5) bond length is 1.66 Å. The Si(1)-O(6) bond length is 1.66 Å. Both Si(1)-O(4) bond lengths are 1.65 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.29 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(3) bond length is 1.31 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Sn(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Na(1), two equivalent Na(2), one Sn(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Na(2), one Sn(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a distorted tetrahedral 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.