2-Amino-5-chloro-pyridinium 3-carb-oxy-4-hy-droxy-benzene-sulfonate

The asymmetric unit of the title salt, C(5)H(6)ClN(2) (+)·C(7)H(5)O(6)S(-), contains two independent 2-amino-5-chloro-pyridinium cations and two independent 3-carb-oxy-4-hy-droxy-benzene-sulfonate anions. In both anions, the O atoms of the sulfonate group are disordered over two sets of positions, with occupancy ratios of 0.47 (5):0.53 (5) and 0.50 (8):0.50 (8). In each anion, an intra-molecular O-H⋯O hydrogen bond generating an S(6) motif is observed. In the crystal structure, the cations and anions are linked via N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, forming a two-dimensional network parallel to (110). The structure is further stabilized by π-π inter-actions between cations and anions [centroid-centroid distance = 3.5454 (12) Å]. The crystal studied was a non-merohedral twin, with a ratio of the twin components of 0.715 (3):0.285 (3).