The title salt, C5H11N2S(+)·C7H4ClO2 (-), comprises a 2-amino-3-ethyl-4,5-di-hydro-1,3-thia-zol-3-ium cation in which the five-membered ring adopts an envelope conformation with the methyl-ene C adjacent to the S atom being the flap, and a planar 3-chloro-benzoate 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 carboxyl-ate 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 inter-actions to form a supra-molecular chain along the a-axis direction.
Keywords: 2-amino-3-ethyl-4,5-dihydro-1,3-thiazol-3-ium cation; 3-chlorobenzoate anion; crystal structure; hydrogen bonding; salt.