title: Isopropyl-aminium 2-carb-oxy-4,5-di-chloro-benzoate.
abstract: In the structure of the 1:1 proton-transfer compound of isopropyl-amine with 4,5-dichloro-phthalic 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 inter-actions 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 carboxyl-ate O atom]. However, the syn-related proton of the carboxylic acid group forms the common short intra-molecular O-H⋯O(carbox-yl) hydrogen bond.
authors.forename: Graham
authors.initials: G
authors.lastname: Smith
authors.forename: Urs D
authors.initials: UD
authors.lastname: Wermuth