Acta Cryst. (2013). E69, o1060-o1061 [ doi:10.1107/S1600536813015389 ]
Abstract: The asymmetric unit of the title compound, C5H7N2+.I3-, consists of one 2-aminopyridin-1-ium cation (apyH+) and one triiodide anion, both located in general postions. The apyH+ cation is planar within the experimental uncertainties. The short N-C distance [1.328 (5) Å] of the exocyclic NH2 group is typical for the imino-form of protonated 2-aminopyridines. Consequently, the bond lengths within the six-membered ring vary significantly. The geometric parameters of the triiodide anion are in the typical range, with bond lengths of 2.8966 (3) and 2.9389 (3) Å and a bond angle of 176.02 (1)°. In the crystal, N-H I hydrogen bonds connect adjacent ions into screwed chains along the b-axis direction. These chains are twisted pairwise into rectangular rods. The pyridinium moieties of neighbouring rods are arranged parallel to each other with a plane-to-plane distance of 3.423 (5) Å.
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