Na2SO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. S(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-51°. There are three 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 S(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one S(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), two equivalent Na(2), and one S(1) atom.
Na2SO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NaO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and edges with two equivalent Na(1)O6 octahedra. Both Na(1)-O(1) bond lengths are 2.33 Å. Both Na(1)-O(2) bond lengths are 2.48 Å. Both Na(1)-O(3) bond lengths are 2.26 Å. In the second Na site, Na(2) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), and four equivalent O(3) atoms. There is one shorter (2.54 Å) and one longer (2.67 Å) Na(2)-O(1) bond length. There is one shorter (2.38 Å) and one longer (2.91 Å) Na(2)-O(2) bond length. There are two shorter (2.36 Å) and two longer (2.91 Å) Na(2)-O(3) bond lengths. S(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SO4 tetrahedra that share corners with six equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-51°. The S(1)-O(1) bond length is 1.49 Å. The S(1)-O(2) bond length is 1.48 Å. Both S(1)-O(3) bond lengths are 1.47 Å. There are three 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 S(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one S(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), two equivalent Na(2), and one S(1) atom.