2. Experimental

The title salt, C5H11N2S +C7H4ClO2, comprises a 2-amino-3-ethyl-4,5-dihydro-1,3-thiazol-3-ium cation in which the five-membered ring adopts an envelope conformation with the methylene C adjacent to the S atom being the flap, and a planar 3-chlorobenzoate anion (r.m.s. deviation for the 10 non-H atoms = 0.021 Å). The most prominent feature of the crystal packing are N—H O hydrogen bonds whereby the two amine H atoms bridge two carboxylate O atoms resulting in the formation of a centrosymmetric 12-membered { HNH OCO}2 synthon involving two cations and two anions. These aggregates are linked by C—H O interactions to form a supramolecular chain along the a-axis direction