Experimental Crystal data

R factor = 0.014; wR factor = 0.039; data-to-parameter ratio = 16.7. In the title compound, C7H6INO3, the 12 non-H atoms are planar, with an r.m.s. deviation of 0.016 Å. A close intra-molecular I O interaction [3.0295 (13) Å] is present. Inter-molecular I O interactions [3.3448 (13) Å] lead to the formation of zigzag chains along the b axis. These are assembled into layers by weak – interactions [centroid– centroid distance = 3.8416 (9) Å], and the layers stack along the a axis, being connected by C—H O contacts. Related literature For general background to halogen bonding, see: Metrangolo et al. (2008); Pennington et al. (2008). For previous structural studies probing iodo–nitro interactions, see: Glidewell et al. (2002, 2004); Garden et al. (2002). For van der Waals radii, see