3,4,7,8-Tetra-methyl-1,10-phenanthrolin-1-ium nitrate monohydrate.

In the crystal of the title compound, C(16)H(17)N(2) (+)·NO(3) (-)·H(2)O, the tetra-methyl-1,10-phenanthrolinium cations, nitrate anions and lattice water mol-ecules are all located on a mirror plane with the methyl H atoms of the cation equally disordered over two sites about the mirror plane. The cation, anion and water mol-ecule are linked by O-H⋯O and N-H⋯O hydrogen bonds into a sheet parallel to the bc plane. π-π stacking between phenanthroline ring systems is observed in the crystal structure, the centroid-centroid distance being 3.4745 (6) Å.