3-Acetylbenzoic acid

Abstract

In the crystal structure of the title compound, C9H8O3, essentially planar mol­ecules [the carboxyl group makes a dihedral angle of 4.53 (7)° with the plane of the ring, while the acid group forms a dihedral angle of 3.45 (8)° to the ring] aggregate by centrosymmetric hydrogen-bond pairing of ordered carboxyl groups. This yields dimers which have two orientations in a unit cell, creating a herringbone pattern. In addition, two close C—H⋯O inter­molecular contacts exist: one is between a methyl H atom and the ketone of a symmetry-related mol­ecule and the other involves a benzene H atom and the carboxyl group O atom of another mol­ecule. The crystal studied was a non-merohedral twin with twin law [100, 00, 0] and a domain ratio of 0.8104(14): 0.1896(14).