NaAl(SO4)2 crystallizes in the monoclinic C2/m space group. Na(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1) and four equivalent O(2) atoms. Al(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form AlO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra. S(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-44°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Na(1) and one S(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one S(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Al(1) and one S(1) atom.
NaAl(SO4)2 crystallizes in the monoclinic C2/m space group. Na(1) is bonded in a distorted hexagonal planar geometry to two equivalent O(1) and four equivalent O(2) atoms. Both Na(1)-O(1) bond lengths are 2.54 Å. All Na(1)-O(2) bond lengths are 2.63 Å. Al(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form AlO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra. Both Al(1)-O(3) bond lengths are 1.86 Å. All Al(1)-O(2) bond lengths are 1.92 Å. S(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SO4 tetrahedra that share corners with three equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 34-44°. The S(1)-O(1) bond length is 1.45 Å. The S(1)-O(3) bond length is 1.48 Å. Both S(1)-O(2) bond lengths are 1.51 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Na(1) and one S(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Al(1), and one S(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Al(1) and one S(1) atom.