Stoichiometric and polymorphic salt of imidazolium picrate monohydrate

The asymmetric unit of the title co-crystal salt, 1H-imidazol-3-ium 2,4,6-tri-nitro-phenolate monohydrate, C₄H₇N₂⁺·C₆H₂N₃O₇^-·H₂O, contains one imidazolium cation, one picrate anion and one solvent water mol-ecule of crystallization. The phenolic proton has been transferred to an imidazole N atom. In the crystal, the components are linked by N-H⋯O and O-H⋯O hydrogen bonds into a three-dimensional network which is further consolidated by weak C-H⋯O hydrogen bonds. In addition, π-π stacking inter-actions occur between pairs of imidazolium cations and picrate anions. If only the classical N-H⋯O and O-H⋯O hydrogen bonds are considered, the component ions are linked into a three-dimensional threefold inter-penetrating network of the topological type utp [or (10,3)-d]. Hirshfeld surface analysis indicates the crystal structure is mainly stabilized by H⋯·O contacts of the hydrogen bonds.