organic papers Acta Cryst. (2007). E63, o2359–o2360 doi:10.1107/S1600536807015577 Hansen et al.  C 7 H 7 NO 2 o2359 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368 Redetermination of 3-hydroxybenzamide Lars Kr. Hansen, a * German L. Perlovich b,c and Annette Bauer-Brandl b a Department of Chemistry, University of Tromsø, 9037 Tromsø, Norway, b Department of Pharmaceutics and Biopharmaceutics, University of Tromsø, 9037 Tromsø, Norway, and c Institute of Solution Chemistry, Russian Academy of Sciences, 153045 Ivanovo, Russian Federation Correspondence e-mail: larsk@chem.uit.no Key indicators Single-crystal X-ray study T = 293 K Mean (C–C) = 0.003 A ˚ R factor = 0.046 wR factor = 0.033 Data-to-parameter ratio = 9.3 For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e. Received 27 March 2007 Accepted 29 March 2007 # 2007 International Union of Crystallography All rights reserved The crystal structure of the title compound, C 7 H 7 NO 2 , has been redetermined [Katsube, Y. (1966). Bull. Chem. Soc. Jpn, 39, 2576–2588] to higher precision and with the hydrogen- bonding scheme established. Comment Hydroxybenzamides (I), (II) and (III) are often used as pro- drug compounds to model various physico-chemical processes of the drug molecules. Their different hydrogen-bonding patterns help to establish their structures and determine their solubilities. The crystal structure of 2-hydroxybenzamide (salicyl- amide), (I), has been described in detail in the literature (Sasada et al., 1964; Pertlik, 1990), whereas the structure of 4- hydroxybenzamide, (III), has not been reported at all. The structure of 3-hydroxybenzamide, (II), was studied some time ago by Katsube (1966) to moderate precision. Here we present a high-precision redetermination of (II) (Fig. 1) and describe its hydrogen-bonding scheme (Table 1). The bond lengths and angles for (II) are within their normal ranges (Allen et al., 1987). The data obtained by us for the non-H atoms are consistent with Katsube’s, but improved by about a factor of twenty in precision. For example, C7—O1 = 1.245 (2) A ˚ , compared with 1.24 (7) A ˚ in Katsube’s study. The dihedral angle between the mean plane of the aromatic ring and the plane of C7/N1/O1 is 22.9 (2)  . The packing of (II) is shown in Fig. 2. The molecules form (101) layers held together by N—HO and O—HO hydrogen bonds. The layers interact with each other by van der Waals forces. The hydrogen-bond network can be described by the graph set assignments introduced by Etter (1990) as C(4), C(8), and R 2 2 (14). Experimental A commercial sample of 3-hydroxybenzamide (Sigma–Aldrich Co. Ltd, St Louis, USA) was used. Crystals of (II) were grown by slow evaporation of a methanol solution.