p-Chloro-, p-bromo- and two polymorphs of p-iodo­aceto­phenone

The title p-haloaceto­phenones, C₈H₇XO (X = Cl, Br and I), have different packing modes. The chloro compound contains H⋯O and H⋯Cl contacts, but no Cl⋯O contacts. The bromo compound and one polymorph (A) of the iodo compound are isomorphous, with significant X⋯O contacts [Br⋯O = 3.320 (4) Å and I⋯O = 3.374 (5) Å]. In the other polymorph (B) of the iodo compound, the I⋯O distance is 3.082 (4) Å. Both polymorphs contain C—H⋯π contacts; these contacts are shorter in A than in B.