3-Amino-4-hydroxybenzenesulfonic Acid Hemihydrate

The title compound (3-ammonio-4-hydroxybenzenesulfonate hemihydrate, C₆H₇NO₄S.½H₂O) crystallizes with two zwitterionic sulfonic acid molecules and one water molecule in the asymmetric unit. The acid molecules pack in layers in which the phenyl rings are nearly coplanar and the polar functional groups are directed towards adjacent layers. These layers stack so that the molecules of one slab are approximately orthogonal to those of the next. There is an extensive network of hydrogen bonds involving the water molecule and the ammonium, hydroxyl and sulfonate groups.

-1