1,10-Phenanthrolinium 4-chloro-2-hydroxy­benzoate–1,10-phenanthroline–4-chloro-2-hydroxy­benzoic acid (1/1/1)

The title compound, C(12)H(9)N(2) (+)·C(7)H(4)ClO(3) (−)·C(12)H(8)N(2)·C(7)H(5)ClO(3), contains one phenanthrolinium (Hphen) cation, one phenanthroline (phen) mol­ecule, one 4-chloro-2-hydroxy­benzoate anion (hcba) and one 4-chloro-2-hydroxy­benzoic acid (Hhcba) mol­ecule in the asymmetric unit. The phen mol­ecule is approximately parallel to Hphen, making a dihedral angle of 1.98 (6)°. The centroid–centroid distance between pyridine rings of adjacent phen and Hphen species is 3.7718 (15) Å, and that between the benzene and pyridine rings of adjacent phen and Hphen species is 3.7922 (16) Å, indicative of π–π stacking inter­actions. The crystal structure contains an extensive network of classical (O—H⋯O, N—H⋯N and O—H⋯Cl) and weak (C—H⋯O and C—H⋯N) hydrogen bonds. Finally, C—H⋯π inter­actions are seen between Hphen and hcba and between phen and Hhcba in the crystal structure. The hydroxy group of the anion is disordered over the two sites ortho to the carboxylate group in a 0.75:0.25 ratio.