Na4Sr(SiO3)3 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(9) atom to form distorted NaO6 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. In the second Na site, Na(2) is bonded in a distorted bent 120 degrees geometry to one O(2), one O(4), and one O(6) atom. In the third Na site, Na(3) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. In the fourth Na site, Na(4) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(9) atom. Sr(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. In the second Si site, Si(2) is bonded to one O(1), one O(6), one O(7), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. In the third Si site, Si(3) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Na(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 are 40°. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Sr(1), one Si(2), and one Si(3) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Sr(1), and one Si(3) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Sr(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Sr(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Sr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Sr(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Sr(1), one Si(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Sr(1), one Si(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Sr(1), and one Si(2) atom.
Na4Sr(SiO3)3 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(2), one O(3), one O(4), one O(5), one O(6), and one O(9) atom to form distorted NaO6 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 Na(1)-O(2) bond length is 2.54 Å. The Na(1)-O(3) bond length is 2.54 Å. The Na(1)-O(4) bond length is 2.54 Å. The Na(1)-O(5) bond length is 2.54 Å. The Na(1)-O(6) bond length is 2.49 Å. The Na(1)-O(9) bond length is 2.54 Å. In the second Na site, Na(2) is bonded in a distorted bent 120 degrees geometry to one O(2), one O(4), and one O(6) atom. The Na(2)-O(2) bond length is 2.26 Å. The Na(2)-O(4) bond length is 2.26 Å. The Na(2)-O(6) bond length is 2.91 Å. In the third Na site, Na(3) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The Na(3)-O(5) bond length is 2.26 Å. The Na(3)-O(6) bond length is 2.22 Å. In the fourth Na site, Na(4) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(9) atom. The Na(4)-O(3) bond length is 2.26 Å. The Na(4)-O(9) bond length is 2.26 Å. Sr(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Sr(1)-O(1) bond length is 2.84 Å. The Sr(1)-O(2) bond length is 2.61 Å. The Sr(1)-O(3) bond length is 2.61 Å. The Sr(1)-O(4) bond length is 2.61 Å. The Sr(1)-O(5) bond length is 2.61 Å. The Sr(1)-O(6) bond length is 2.69 Å. The Sr(1)-O(7) bond length is 2.84 Å. The Sr(1)-O(8) bond length is 2.84 Å. The Sr(1)-O(9) bond length is 2.61 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(4), one O(5), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. The Si(1)-O(4) bond length is 1.59 Å. The Si(1)-O(5) bond length is 1.59 Å. The Si(1)-O(7) bond length is 1.67 Å. The Si(1)-O(8) bond length is 1.67 Å. In the second Si site, Si(2) is bonded to one O(1), one O(6), one O(7), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 40°. The Si(2)-O(1) bond length is 1.67 Å. The Si(2)-O(6) bond length is 1.63 Å. The Si(2)-O(7) bond length is 1.67 Å. The Si(2)-O(9) bond length is 1.59 Å. In the third Si site, Si(3) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Na(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 are 40°. The Si(3)-O(1) bond length is 1.67 Å. The Si(3)-O(2) bond length is 1.59 Å. The Si(3)-O(3) bond length is 1.59 Å. The Si(3)-O(8) bond length is 1.67 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Sr(1), one Si(2), and one Si(3) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Sr(1), and one Si(3) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Sr(1), and one Si(3) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Sr(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Sr(1), and one Si(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Sr(1), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Sr(1), one Si(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Sr(1), one Si(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Sr(1), and one Si(2) atom.