A monoclinic polymorph of cysteamine hydrochloride

The title compound (systematic name: 2-mercaptoethanaminium chloride), C2H8NS+·Cl−, the hydrochloride salt of cysteamine, in contrast to the previously reported triclinic polymorph [Kim et al. (2002 ▶). Polyhedron, 21, 225–228], crystallized in the monoclinic crystal system. In the crystal, the cysteaminium cations are linked to the chloride anions via one S—H⋯Cl and three N—H⋯Cl hydrogen bonds. Two-dimensional slab-like networks are formed, which are stacked in [100]. This arrangement is similar to that observed in the triclinic polymorph.