8-Methoxy-3,4-methylenedioxy-10-nitrophenanthrene1-carboxylic acid

In the crystal structure of the title compound, C17H11NO7, the phenanthrene ring system and the five-membered ring are almost coplanar. The carboxy and nitro groups lie above and below the plane, respectively, owing to steric effects. The hydroxy groups form strong intermolecular O-H center dot center dot center dot O hydrogen bonds with the carbonyl group O atom. The carboxy groups of pairs of molecules form centrosymmetric rings via pairs of intermolecular hydrogen bonds.