title: Crystal structure of 6,7-di-chloro-4-oxo-4H-chromene-3-carbaldehyde.
abstract: In the title compound, C10H4Cl2O3, a dichlorinated 3-formyl-chromone, 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, mol-ecules 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 inter-actions [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)°].
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ishikawa
keywords: chromone; crystal structure; halogen–halogen contact; hydrogen bonding; stacking inter­action