2-Hydroxy-7-nitrocyclohepta-2,4,6-trien-1-one

Abstract

The title compound, also known as 7-nitrotropolone, C7H5NO4, exists in the crystalline state as the 2-hydroxy-7-nitrocyclohepta-2,4,6-trien-1-one tautomer and not as 2-hydroxy-3-nitrocyclohepta-2,4,6-trien-1-one. The dihedral angle between the ring and the nitro group is 70.3 (2)°. In the crystal, neighbouring molecules are linked into dimers by a pair of O—H...O hydrogen bonds. In addition, the crystal is stabilized by O...π [3.4039 (14) Å] and O...O [3.073 (2) Å] interactions.