4-Nitroanilinium triiodide monohydrate

In the title compound, C(6)H(7)N(2)O(2)(+)center dot I(3)(-)center dot H(2)O, the triiodide anions form two-dimensional sheets along the a and c axes. These sheets are separated by the 4-nitroanilinium cations and water molecules, 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 interaction is between the nitro group, the water molecule 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)degrees. These two strong hydrogen-bonding interactions also cause the benzene rings to pack off-centre from one another, with an edge-on-edge pi-pi stacking distance of 3.634 (6) angstrom and a centroid-centroid separation of 4.843 (2) angstrom.