6-Chloro-4-oxo-4H-chromene-3-carb-aldehyde

In the title compound, C10H5ClO3, a chlorinated 3-formyl-chromone derivative, the non-H atoms are essentially coplanar (r.m.s. deviation = 0.0456 Å) with the largest deviation from the least-squares plane [0.1136 (16) Å] being found for the ring-bound carbonyl O atom. In the crystal, mol-ecules are linked through stacking inter-actions along the b axis [shortest centroid-centroid distance between the pyran and benzene rings = 3.4959 (15) Å].