title: Fleroxacin hydrochloride hydrate.
abstract: In the structure of the title compound, 4-[3-carboxy-6,8-difluoro-1-(2-fluoroethyl)-1,4-dihydro-4-oxo-7-quinolyl]-1-methylpiperazinium chloride hydrate, C(17)H(19)F(3)N(3)O(3)(+).Cl(-).H(2)O, the quinoline and its substituents, except for the fluoroethyl group, are coplanar, while the piperazinium moiety exists in a chair form. There are pi-pi-stacking interactions between the quinoline rings, and intra- and intermolecular hydrogen bonds in the crystal.