2-Amino-5-chloro-pyridinium 2-carb-oxy-benzoate-benzene-1,2-dicarb-oxy-lic acid (3/1)

The asymmetric unit of the title compound, 3C(5)H(6)ClN(2) (+)·3C(8)H(5)O(4) (-)·C(8)H(6)O(4), contains three independent 2-amino-5-chloro-pyridinium cations, three independent hydrogen phthal-ate anions and one phthalic acid mol-ecule. In the crystal structure, there are two kinds of supra-molecular tapes. One is formed by two independent cations with two anions through N-H⋯O and C-H⋯O hydrogen bonds. Another one is formed by the other cation and anion, and the phthalic acid mol-ecule via N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds. These two tapes are connected by an O-H⋯O hydrogen bond, forming a double-tape structure.