2-Amino-5-nitro-pyridinium tetraoxido-rhenate(VII) monohydrate.

All the residues of the title compound, (C(5)H(6)N(3)O(2))[ReO(4)]·H(2)O, are located on general crystallographic positions. The 2-amino-5-nitro-pyridinium cation has a typical planar conformation with one of the nitro O atoms -0.058†(5)†à out of plane; the amine H atoms are also a little out of the main ring plane towards the opposite side of the aforementioned O atom [by 0.02†(4) and 0.04†(4)†à ]. The perrhenate anion is nearly ideally tetra-hedral. Three distinct N-H⋯O hydrogen bonds give rise to C(8) zigzag chains running along [100]. R(4) (4)(12) rings involving the two hydrogen bonds in which the water mol-ecules inter-act with the perrhenate anions are also present.