organic papers Acta Cryst. (2006). E62, o2749–o2750 doi:10.1107/S1600536806021106 Bu ¨ yu ¨ kgu ¨ ngo ¨ r and Odabas ¸og ˇlu C 6 H 9 N 2 + C 8 H 5 O 3 H 2 O o2749 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368 2-Amino-6-methylpyridinium 2-formylbenzoate monohydrate Orhan Bu ¨yu ¨kgu ¨ngo ¨r a and Mustafa Odabas ¸og ˇlu b * a Department of Physics, Faculty of Arts and Sciences, Ondokuz Mayıs University, TR-55139 Kurupelit Samsun, Turkey, and b Department of Chemistry, Faculty of Arts and Sciences, Ondokuz Mayıs University, TR-55139 Kurupelit Samsun, Turkey Correspondence e-mail: muodabas@omu.edu.tr Key indicators Single-crystal X-ray study T = 296 K Mean (C–C) = 0.003 A ˚ R factor = 0.041 wR factor = 0.117 Data-to-parameter ratio = 12.1 For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e. Received 11 May 2006 Accepted 2 June 2006 # 2006 International Union of Crystallography All rights reserved The title compound, C 6 H 9 N 2 + C 8 H 5 O 3 H 2 O, contains hydrogen-bonded [R 2 2 (8)R 4 2 (8)R 2 2 (8)] motifs involving 2-amino-6-methylpyridinium and 2-carbonylbenzoate ions. These motifs are connected by three O—HO hydrogen bonds involving two water O atoms. Comment The title compound was obtained by the reaction of 2-amino- 6-methylpyridine and 2-formylbenzoic acid. The copper(II) complexes of 2-aminopyridinium carboxylates have important properties in the applications in pharmaceuticals, fungicides, oxygen transfer, oxidative addition, homogenous hydrogena- tion, gas occlusion compounds and solvent extraction processes (Lah et al., 2001; Yang et al., 1995). Intermolecular interaction analyses in crystalline systems are very important in supramolecular chemistry, which can be defined as the chemistry (Braga et al., 2002). These interactions are respon- sible for crystal packing, and through an understanding of such interactions we can comprehend collective properties and design new crystals with specific physical and chemical prop- erties (Lam & Mak, 2000). We have been interested in hydrogen-bonded systems formed by organic amines and carboxylic acids that generate molecular assemblies (Odaba- s ¸og ˇlu, Bu ¨ yu ¨ kgu ¨ ngo ¨r & Lo ¨ nnecke, 2003; Odabas ¸og ˇlu, Bu ¨ yu ¨k- gu ¨ ngo ¨ r, Turgut et al., 2003; Bu ¨ yu ¨ kgu ¨ ngo ¨r et al., 2004; Bu ¨ yu ¨ kgu ¨ ngo ¨r & Odabas ¸og ˇlu, 2002, 2003; Odabas ¸og ˇlu & Bu ¨ yu ¨ kgu ¨ ngo ¨ r, 2006a,b). The present work is part of a struc- tural study of compounds of organic ammonium systems with hydrogen-bond donors and we report here the structure of the title compound, (I) (Fig. 1). In (I), the 2-amino-6-methylpyridinium ions are linked to the 2-formylbenzoate ions through N—HO hydrogen bonds and generate [R 2 2 (8) R 2 4 (8)R 2 2 (8)] motifs (Fig. 2 and Table 1). These motifs are connected by three O—HO hydrogen bonds involving two water O atoms. Experimental The title compound was prepared by mixing 2-amino-6-methyl- pyridine and 2-formylbenzoic acid in a 1:1 molar ratio in 50 ml of