Na2Al2Si3O10 crystallizes in the monoclinic C2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(2), one O(3), and one O(5) atom. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(4), one O(8), and one O(9) atom. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. In the second Al site, Al(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(9) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with two equivalent Si(4)O4 tetrahedra. In the second Si site, Si(2) is bonded to two equivalent O(10) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(2)O4 tetrahedra and corners with two equivalent Si(3)O4 tetrahedra. In the third Si site, Si(3) is bonded to one O(10), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(4), one O(5), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. There are ten inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one Al(1), and one Si(3) atom. In the second O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(2), one Al(2), and one Si(4) atom. In the third O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Al(1), and one Si(4) atom. In the fourth O site, O(6) is bonded in a bent 120 degrees geometry to one Al(2) and one Si(3) atom. In the fifth O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Al(1) and one Si(4) atom. In the sixth O site, O(8) is bonded in a 2-coordinate geometry to one Na(2), one Al(2), and one Si(3) atom. In the seventh O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Si(1), and one Si(4) atom. In the eighth O site, O(10) is bonded in a 2-coordinate geometry to one Na(1), one Na(2), one Si(2), and one Si(3) atom. In the ninth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one Si(1) atom. In the tenth O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(2), and one Si(2) atom.
Na2Al2Si3O10 crystallizes in the monoclinic C2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(2), one O(3), and one O(5) atom. The Na(1)-O(1) bond length is 2.61 Å. The Na(1)-O(10) bond length is 2.79 Å. The Na(1)-O(2) bond length is 2.82 Å. The Na(1)-O(3) bond length is 2.49 Å. The Na(1)-O(5) bond length is 2.56 Å. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(10), one O(2), one O(4), one O(8), and one O(9) atom. The Na(2)-O(10) bond length is 2.82 Å. The Na(2)-O(2) bond length is 2.62 Å. The Na(2)-O(4) bond length is 2.38 Å. The Na(2)-O(8) bond length is 2.86 Å. The Na(2)-O(9) bond length is 2.73 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, and corners with two equivalent Si(4)O4 tetrahedra. The Al(1)-O(1) bond length is 1.77 Å. The Al(1)-O(3) bond length is 1.79 Å. The Al(1)-O(5) bond length is 1.78 Å. The Al(1)-O(7) bond length is 1.76 Å. In the second Al site, Al(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form AlO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Si(4)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Al(2)-O(2) bond length is 1.77 Å. The Al(2)-O(4) bond length is 1.78 Å. The Al(2)-O(6) bond length is 1.76 Å. The Al(2)-O(8) bond length is 1.75 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and two equivalent O(9) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(1)O4 tetrahedra and corners with two equivalent Si(4)O4 tetrahedra. Both Si(1)-O(1) bond lengths are 1.63 Å. Both Si(1)-O(9) bond lengths are 1.66 Å. In the second Si site, Si(2) is bonded to two equivalent O(10) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with two equivalent Al(2)O4 tetrahedra and corners with two equivalent Si(3)O4 tetrahedra. Both Si(2)-O(10) bond lengths are 1.66 Å. Both Si(2)-O(2) bond lengths are 1.63 Å. In the third Si site, Si(3) is bonded to one O(10), one O(3), one O(6), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, and corners with two equivalent Al(2)O4 tetrahedra. The Si(3)-O(10) bond length is 1.68 Å. The Si(3)-O(3) bond length is 1.64 Å. The Si(3)-O(6) bond length is 1.62 Å. The Si(3)-O(8) bond length is 1.63 Å. In the fourth Si site, Si(4) is bonded to one O(4), one O(5), one O(7), and one O(9) atom to form SiO4 tetrahedra that share  a cornercorner with one Al(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra, and corners with two equivalent Al(1)O4 tetrahedra. The Si(4)-O(4) bond length is 1.65 Å. The Si(4)-O(5) bond length is 1.63 Å. The Si(4)-O(7) bond length is 1.63 Å. The Si(4)-O(9) bond length is 1.67 Å. There are ten inequivalent O sites. In the first O site, O(3) is bonded in a distorted trigonal planar geometry to one Na(1), one Al(1), and one Si(3) atom. In the second O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(2), one Al(2), and one Si(4) atom. In the third O site, O(5) is bonded in a distorted trigonal planar geometry to one Na(1), one Al(1), and one Si(4) atom. In the fourth O site, O(6) is bonded in a bent 120 degrees geometry to one Al(2) and one Si(3) atom. In the fifth O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Al(1) and one Si(4) atom. In the sixth O site, O(8) is bonded in a 2-coordinate geometry to one Na(2), one Al(2), and one Si(3) atom. In the seventh O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Si(1), and one Si(4) atom. In the eighth O site, O(10) is bonded in a 2-coordinate geometry to one Na(1), one Na(2), one Si(2), and one Si(3) atom. In the ninth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one Si(1) atom. In the tenth O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Al(2), and one Si(2) atom.