title: Gallic Acid.
abstract: Anhydrous 3,4,5-trihy-droxy-benzoic acid, C(7)H(6)O(5), is essentially planar, with its non-H atoms exhibiting mean and maximum deviations from coplanarity of 0.014 and 0.0377 (5) Å, respectively. The C-C-C-OH torsion angle about the bond linking the carboxyl group to the benzene ring is -0.33 (10)°. In the crystal, the -COOH groups form centrosymmetric hydrogen-bonded cyclic dimers [graph set R(2) (2)(8)] and the phenolic -OH groups participate in both intra- and inter-molecular hydrogen bonds, forming a three-dimensional network structure.
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhao
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
authors.forename: Frank R
authors.initials: FR
authors.lastname: Fronczek