title: 3-Acetyl-benzoic acid.
abstract: In the crystal structure of the title compound, C(9)H(8)O(3), essentially planar mol-ecules [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 inter-molecular contacts exist: one is between a methyl H atom and the ketone of a symmetry-related mol-ecule and the other involves a benzene H atom and the carboxyl group O atom of another mol-ecule. 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).
authors.affiliation: Carl A. Olson Memorial Laboratories, Department of Chemistry, Rutgers University, Newark, NJ 07102, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Fixler
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Newman
authors.forename: Roger A
authors.initials: RA
authors.lastname: Lalancette
authors.forename: Hugh W
authors.initials: HW
authors.lastname: Thompson