Redetermination and invariom refinement of 1-cyclo-propyl-6-fluoro-4-oxo-7-(piperazin-4-ium-1-yl)-1,4-dihydro-quinoline-3-carboxyl-ate hexa-hydrate at 120 K.

The structure of the title compound, C(17)H(18)FN(3)O(3)·6H(2)O, has been redetermined at 120 K. An invariom refinement, a structural refinement using aspherical scattering factors from theoretically predicted multipole population parameters, yields accurate geometry and anisotropic displacement parameters, including hydrogen-bonding parameters. All potential hydrogen-bond donors and acceptors are involved in hydrogen bonding, forming an intricate three-dimensional network of N-H⋯O and O-H⋯O bonds.