organic compounds
In the triclinic polymorph of 2-iodo-4-nitroaniline, C6H5IN2O2, space group P, the molecules are linked by paired N-HO hydrogen bonds into C(8)[R(6)] chains of rings. These chains are linked into sheets by nitroI interactions, and the sheets are pairwise linked by aromatic --stacking interactions. In the orthorhombic polymorph, space group Pbca, the molecules are linked by single N-HO hydrogen bonds into spiral C(8) chains; the chains are linked by nitroO interactions into sheets, each of which is linked to its two immediate neighbours by aromatic --stacking interactions, so producing a continuous three-dimensional structure.
organic compounds
Molecules of the title compound, C12H10N2O2, are markedly non-planar. There is an intramolecular N-HO hydrogen bond, and the molecules are linked into zigzag chains by a single C-HO hydrogen bond. Comparisons are made with the supramolecular aggregation in isomeric amino-nitro derivatives, and in some N-methylnitroanilines.