3-Aminobenzenesulfonic Acid: A Disappearing Polymorph

We have identified and characterized the existence of two new polymorphic forms (orthorhombic needles and monoclinic plates) of 3-aminobenzenesulfonic acid, one of which was a previously unrecognized polymorphic form. The circumstances and events indicate that Form I may be considered a disappearing crystal form. The production of Form III was a serendipitous occurrence in an attempt to use the strategy of tailor-made additives to reobtain Form I; although unsuccessful, it has once more shown the need to explore as much of the chemical potential surface as possible even in a system as seemingly simple as this one.