Crystal structure of 6,7-dichloro-4-oxo-4H-chromene-3-carbaldehyde

In the title compound, C10H4Cl2O3, a dichlorinated 3-formylchromone, the non-H atoms of the 4H-chromene ring are essentially coplanar (r.m.s. = 0.0188 Å), with the largest deviation from the least-squares plane [0.043 (2) Å] being for the pyran C=O C atom. The α,β-unsaturated carbonyl O atom deviates from the least-square plane by 0.124 (2) Å. The dihedral angle between the chromone and formyl least-square planes is 6.76 (3)°. In the crystal, molecules are linked through C—H...O hydrogen bonds between the translation-symmetry and inversion-symmetry equivalents to form tetrads, which are further assembled by stacking interactions [centroid–centroid distance between the benzene rings = 3.769 (2) Å]. van der Waals contacts are found between the Cl atoms at the 6-position and the Cl atoms at 7-position of the glide-reflection-symmetry equivalents [Cl...Cl = 3.4785 (16) Å, C—Cl...Cl = 160.23 (7)° and Cl...Cl—C = 122.59 (7)°]