4-Nitro-anilinium triiodide monohydrate.

In the title compound, C(6)H(7)N(2)O(2) (+)·I(3) (-)·H(2)O, the triiodide anions form two-dimensional sheets along the a and c axes. These sheets are separated by the 4-nitro-anilinium cations and water mol-ecules, which form part of an extended hydrogen-bonded chain with the triiodide along the c axis, represented by the graph set C(3) (3)(14). The second important hydrogen-bonding inter-action is between the nitro group, the water mol-ecule and the anilinium group, which forms an R(2) (2)(6) ring and may be the reason for the deviation of the torsion angle between the benzene ring and the nitro group from 180 to 163.2 (4)°. These two strong hydrogen-bonding inter-actions also cause the benzene rings to pack off-centre from one another, with an edge-on-edge π-π stacking distance of 3.634 (6) Šand a centroid-centroid separation of 4.843 (2) Å.