1-Ethyl-5-iodoindoline-2,3-dione

There are two independent molecules in the asymmetric unit of the title compound, C10H8INO2, which differ in the degree of planarity. The iodoindoline-2,3-dione skeleton of molecule 1 is essentially planar [mean deviation = 0.003 (2) angstrom for the nine non-H atoms of the indoline core, with a maximum deviation of 0.033 (1) angstrom for the I atom]. The I atom and O atom in the 3-position of molecule 2 deviate by 0.195 (1) and 0.120 (2) angstrom, respectively, from the least-squares plane through the nine non-H atoms of the indoline core. Molecules 1 and 2 are roughly coplanar, the mean planes through their cores making a dihedral angle of 6.84 (1)degrees. This coplanarity results in a layer-like structure parallel to (6,11,17) in the crystal, the distance between adjacent least-squares planes through the cores of molecules 1 and 2 being 3.37 (1) angstrom. In such a layer, molecules 1 and 2 are linked by C-H center dot center dot center dot O hydrogen bonds, forming chains along [11 (1) over bar]. The chains are further coupled to construct a kind of double-chain structure via I center dot center dot center dot O interactions [3.270 (2) angstrom].