Isopropyl­aminium 2-carb­oxy-4,5-di­chloro­benzoate

In the structure of the 1:1 proton-transfer compound of isopropyl­amine with 4,5-dichloro­phthalic acid, C(3)H(10)N(+)·C(8)H(3)Cl(2)O(4) (−), the three cation H-atom donors associate with three separate carboxyl O-atom anion acceptors, giving conjoint cyclic R (4) (4)(12), R (4) (4)(16) hydrogen-bonding cation–anion inter­actions in a one-dimensional ribbon structure. In the anions, the carboxyl groups lie slightly out of the plane of the benzene ring [maximum deviations = 0.439 (1) for a carboxylic acid O atom and 0.433 (1) Å for a carboxyl­ate O atom]. However, the syn-related proton of the carboxylic acid group forms the common short intra­molecular O—H⋯O(carbox­yl) hydrogen bond.