Na3NbSnSi3O12 crystallizes in the monoclinic Cc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted hexagonal planar geometry to one O(1), one O(11), one O(12), one O(2), one O(5), and one O(6) atom. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(2), one O(7), one O(8), and one O(9) atom. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(11), one O(2), one O(5), one O(6), one O(7), and two equivalent O(4) atoms. Nb(1) is bonded to one O(10), one O(12), one O(2), one O(3), one O(6), and one O(7) atom to form NbO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. Sn(1) is bonded to one O(1), one O(11), one O(4), one O(5), one O(8), and one O(9) atom to form SnO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-39°. In the second Si site, Si(2) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-40°. In the third Si site, Si(3) is bonded to one O(1), one O(10), one O(6), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-39°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one Sn(1), and one Si(3) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Nb(1), and one Si(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Sn(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(3), one Sn(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(3), one Nb(1), and one Si(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), one Nb(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Sn(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Sn(1), and one Si(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one Si(3) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Sn(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Nb(1), and one Si(1) atom.
Na3NbSnSi3O12 crystallizes in the monoclinic Cc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted hexagonal planar geometry to one O(1), one O(11), one O(12), one O(2), one O(5), and one O(6) atom. The Na(1)-O(1) bond length is 2.37 Å. The Na(1)-O(11) bond length is 2.59 Å. The Na(1)-O(12) bond length is 2.42 Å. The Na(1)-O(2) bond length is 2.66 Å. The Na(1)-O(5) bond length is 2.43 Å. The Na(1)-O(6) bond length is 2.53 Å. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(2), one O(7), one O(8), and one O(9) atom. The Na(2)-O(1) bond length is 2.43 Å. The Na(2)-O(10) bond length is 2.66 Å. The Na(2)-O(11) bond length is 2.58 Å. The Na(2)-O(12) bond length is 2.64 Å. The Na(2)-O(2) bond length is 2.45 Å. The Na(2)-O(7) bond length is 2.95 Å. The Na(2)-O(8) bond length is 2.93 Å. The Na(2)-O(9) bond length is 2.53 Å. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(11), one O(2), one O(5), one O(6), one O(7), and two equivalent O(4) atoms. The Na(3)-O(11) bond length is 2.44 Å. The Na(3)-O(2) bond length is 2.69 Å. The Na(3)-O(5) bond length is 2.43 Å. The Na(3)-O(6) bond length is 2.49 Å. The Na(3)-O(7) bond length is 2.52 Å. There is one shorter (2.75 Å) and one longer (2.86 Å) Na(3)-O(4) bond length. Nb(1) is bonded to one O(10), one O(12), one O(2), one O(3), one O(6), and one O(7) atom to form NbO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Nb(1)-O(10) bond length is 2.00 Å. The Nb(1)-O(12) bond length is 2.03 Å. The Nb(1)-O(2) bond length is 2.08 Å. The Nb(1)-O(3) bond length is 1.93 Å. The Nb(1)-O(6) bond length is 2.04 Å. The Nb(1)-O(7) bond length is 2.01 Å. Sn(1) is bonded to one O(1), one O(11), one O(4), one O(5), one O(8), and one O(9) atom to form SnO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Sn(1)-O(1) bond length is 2.09 Å. The Sn(1)-O(11) bond length is 2.09 Å. The Sn(1)-O(4) bond length is 2.05 Å. The Sn(1)-O(5) bond length is 2.09 Å. The Sn(1)-O(8) bond length is 2.00 Å. The Sn(1)-O(9) bond length is 2.05 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-39°. The Si(1)-O(11) bond length is 1.64 Å. The Si(1)-O(12) bond length is 1.64 Å. The Si(1)-O(3) bond length is 1.66 Å. The Si(1)-O(4) bond length is 1.63 Å. In the second Si site, Si(2) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-40°. The Si(2)-O(2) bond length is 1.67 Å. The Si(2)-O(5) bond length is 1.63 Å. The Si(2)-O(7) bond length is 1.66 Å. The Si(2)-O(9) bond length is 1.62 Å. In the third Si site, Si(3) is bonded to one O(1), one O(10), one O(6), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Nb(1)O6 octahedra and corners with two equivalent Sn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-39°. The Si(3)-O(1) bond length is 1.63 Å. The Si(3)-O(10) bond length is 1.67 Å. The Si(3)-O(6) bond length is 1.65 Å. The Si(3)-O(8) bond length is 1.62 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one Sn(1), and one Si(3) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Nb(1), and one Si(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Nb(1) and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Na(3), one Sn(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(3), one Sn(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal pyramidal geometry to one Na(1), one Na(3), one Nb(1), and one Si(3) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(2), one Na(3), one Nb(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Na(2), one Sn(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Sn(1), and one Si(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Nb(1), and one Si(3) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Sn(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Nb(1), and one Si(1) atom.