Crystal structure of a 1:1 salt of 4-amino­benzoic acid (vitamin B(10)) with pyrazinoic acid

The title 1:1 salt, C(7)H(8)NO(2) (+)·C(5)H(3)N(2)O(2) (−) (systematic name: 4-carb­oxy­anilinium pyrazine-2-carboxyl­ate), was synthesized successfully by slow evaporation of a saturated solution from water–ethanol (1:1 v/v) mixture and characterized by X-ray diffraction (SCXRD, PXRD) and calorimetry (DSC). The crystal structure of the salt was solved and refined at 150 and 293 K. The salt crystallizes with one mol­ecule of 4-amino­benzoic acid (PABA) and one mol­ecule of pyrazinoic acid (POA) in the asymmetric unit. In the crystal, the PABA and POA mol­ecules are associated via COOH⋯N(arom) heterosynthons, which are connected by N—H⋯O hydrogen bonds, creating zigzag chains. The chains are further linked by N—H⋯O hydrogen bonds and π–π stacking inter­actions along the b axis [centroid-to-centroid distances = 3.7377 (13) and 3.8034 (13) Å at 150 and 293 K, respectively] to form a layered three-dimensional structure.