8,10-Diiodo-2,6-dioxo-4λ3-ioda-3,5-dioxatricyclo[5.3.1.04,11]undeca-1(11),7,9-triene-9-carboxylic acid

In the title compound, C9HI3O6·2H2O, the mol­ecule is located on a twofold axis that gives rise to disorder of the carboxyl group. This disorder is correlated with the disorder of one of the H atoms of the water mol­ecule. The carboxyl group is twisted relative to the attached benzene ring by 75.1 (4)°. The intra­molecular I⋯O distance is 2.112 (6) A. Mol­ecules are linked via O—H⋯O hydrogen bonding, C—I⋯O halogen bonding, with I⋯O distances in the range 3.156 (5)–3.274 (6) A, and dipolar C=O⋯C=O inter­actions between the carboxyl and carboxyl­ate groups, with an O⋯C distance of 2.944 (10) A.