A feature of the title compound, sodium 5-amino-2-naphthalenesulfonate
-water (1/4), Na+.C10H8NO3S-.4H(2)O, is that the Na+ ions are coordina
ted by distorted edge-sharing octahedra of water O atoms. The coordina
tion distances around Na+ vary from 2.217(8) to 2.80(1) Angstrom.