2-[(4-Chloro-phen-yl)selan-yl]-3,4-di-hydro-2H-benzo[h]chromene-5,6-dione: crystal structure and Hirshfeld analysis.

The title organoselenium compound, C(19)H(13)ClO(3)Se {systematic name: 2-[(4-chloro-phen-yl)selan-yl]-2H,3H,4H,5H,6H-naphtho-[1,2-b]pyran-5,6-dione}, has the substituted 2-pyranyl ring in a half-chair conformation with the methyl-ene-C atom bound to the methine-C atom being the flap atom. The dihedral angle between the two aromatic regions of the mol-ecule is 9.96†(9)° and indicates a step-like conformation. An intra-molecular Se⋯O inter-action of 2.8122†(13)†à is noted. In the crystal, π-π contacts between naphthyl rings [inter-centroid distance = 3.7213†(12)†à ] and between naphthyl and chloro-benzene rings [inter-centroid distance = 3.7715†(13)†à ], along with C-Cl⋯π(chloro-benzene) contacts, lead to supra-molecular layers parallel to the ab plane, which are connected into a three-dimensional architecture via methyl-ene-C-H⋯O(carbon-yl) inter-actions. The contributions of these and other weak contacts to the Hirshfeld surface is described.