Acta Cryst. (2011). E67, o1509-o1510  [ doi:10.1107/S1600536811018848 ]

A third monoclinic polymorph of 3,4,5-trihydroxybenzoic acid monohydrate

G. Demirtas, N. Dege and O. Büyükgüngör

Abstract: The title compound, C₇H₆O₅·H₂O, is a new polymorph of the structures reported by Jiang et al. (2000) [Acta Cryst. C56, 594-595] and Okabe et al. (2001) [Acta Cryst. E57, o764-o766]. The gallic acid molecule is essentially planar (r.m.s. deviation = 0.550 Å). An intramolecular O-HO hydrogen bond occurs in the gallic acid molecule, which is linked to the water molecule by a further O-HO hydrogen bond. In the crystal, the components are linked by O-HO hydrogen bonds. The hydrogen-bonding pattern differs from those reported for the previous polymorphs.

Online 25 May 2011

Copyright © International Union of Crystallography
IUCr Webmaster