2-Hydroxy-5-nitrobenzaldehyde

The title compound, C7H5NO4, is essentially planar, with a maximum deviation from the mean plane of 0.0116 (11) Å for the hydroxy O atom. The molecular and crystal structure are stabilized by intra- and intermolecular interactions. An intramolecular O—H...O hydrogen bond generates a six-membered ring, producing an S(6) ring motif. The C—H...O interactions result in the formation of C(5) chains and R22(8) rings forming an approximately planar network parallel to (10overline{1}). These planes are interconnected through π–π interactions [centroid–centroid distance 3.582 (2) Å]