4-(3-Carb­oxy-1-ethyl-6-fluoro-4-oxo-1,4-dihydro-7-quinol­yl)-1-methyl­piper­azin­ium picrate

The pefloxacinium cation of the title salt, C(17)H(21)FN(3)O(3) (+)·C(6)H(2)N(3)O(7) (−), is composed of an essentially planar quinoline ring system [maximum deviation = 0.021 (2) Å] and a piperazine ring, which adopts a chair conformation. In the picrate anion, the two O atoms of one of the o-NO(2) groups are disordered over two positions, with an occupancy ratio of 0.56 (4):0.44 (4). In the crystal structure, cations and anions are connected by inter­molecular N—H⋯O, O—H⋯O, C—H⋯O and C—H⋯F hydrogen bonds, forming a three-dimensional network. In addition, π–π inter­actions between the pyridine rings and between the benzene rings of the anions, with centroid–centroid distances of 3.6103 (12) and 3.5298 (11) Å, respectively, are observed.