Diaquabis[2-(2-hydroxyethyl)pyridine- j 2 N,O]cobalt(II) dichloride Ouahida Zeghouan, Fatiha Guenifa, Nasreddine Hadjadj, Lamia Bendjeddou* and Hocine Merazig Unite ´ de Recherche Chimie de l’Environnement et Mole ´culaire Structurale ’CHEMS’, Faculte ´ des Sciences Exactes, Campus Chaabet Ersas, Universite ´ Constantine I, 25000 Constantine, Algeria Correspondence e-mail: Lamiabendjeddou@yahoo.fr Received 29 June 2013; accepted 2 July 2013 Key indicators: single-crystal X-ray study; T = 293 K; mean (C–C) = 0.003 A ˚ ; R factor = 0.020; wR factor = 0.056; data-to-parameter ratio = 13.3. In the title salt, [Co(C 7 H 9 NO) 2 (H 2 O) 2 ]Cl 2 , the Co II cation, located on an inversion center, is N,O-chelated by two hydroxyethylpyridine ligands and coordinated by two water molecules in a distorted O 4 N 2 octahedral geometry. In the crystal, the Cl  anions link with the complex cations via O— HCl hydrogen bonds, forming a three-dimensional supra- molecular architecture. – stacking is observed between the pyridine rings of adjacent molecules [centroid–centroid distance = 3.5810 (11) A ˚ ]. Related literature For applications of pyridine derivatives in the synthesis of coordination polymers, see: Sanudo et al. (2003); Boskovic et al. (2002). For related complexes containing a 2(2-hydroxy- ethyl)pyridine ligand, see: Kong et al. (2009); Mobin et al. (2010). For hydrogen-bond motifs, see: Bernstein et al. (1995). Experimental Crystal data [Co(C 7 H 9 NO) 2 (H 2 O) 2 ]Cl 2 M r = 412.17 Orthorhombic, Pbcn a = 12.8911 (3) A ˚ b = 8.0049 (2) A ˚ c = 16.8757 (4) A ˚ V = 1741.44 (7) A ˚ 3 Z =4 Mo K radiation  = 1.31 mm 1 T = 293 K 0.3  0.2  0.2 mm Data collection Bruker APEXII diffractometer 9407 measured reflections 1535 independent reflections 1419 reflections with I >2(I) R int = 0.015 Refinement R[F 2 >2(F 2 )] = 0.020 wR(F 2 ) = 0.056 S = 1.04 1535 reflections 115 parameters H atoms treated by a mixture of independent and constrained refinement Á max = 0.21 e A ˚ 3 Á min = 0.22 e A ˚ 3 Table 1 Selected bond lengths (A ˚ ). Co1—O1 2.1210 (13) Co1—O1W 2.0715 (13) Co1—N1 2.1537 (14) Table 2 Hydrogen-bond geometry (A ˚ ,  ). D—HA D—H HA DA D—HA O1—H1Cl i 0.84 (2) 2.26 (2) 3.0625 (13) 162 (2) O1W—H1WCl ii 0.932 (11) 2.145 (12) 3.0738 (13) 174.6 (19) O1W—H2WCl iii 0.835 (16) 2.285 (16) 3.1121 (14) 170.4 (15) Symmetry codes: (i) x; y; z  1 2 ; (ii) x þ 1; y; z þ 1 2 ; (iii) x þ 1 2 ; y þ 1 2 ; z þ 1 2 . Data collection: APEX2 (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT; program(s) used to solve structure: SIR2002 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: WinGX (Farrugia, 2012), Mercury (Macrae et al., 2006) and POV-RAY (Persistence of Vision Team, 2004). This work was supported by the Unite ´ de Recherche de Chimie de l’Environnement et Mole ´ culaire Structurale (CHEMS), Universite ´ de Constantine 1, Algeria. Thanks are due to MESRS and ATRST (Ministe ` re de l’Enseignement Supe ´ rieur et de la Recherche Scientifique et l’Agence The ´ matique de Recherche en Sciences et Technologie, Algeria) via the PNR program for financial support. Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU5717). References Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. Boskovic, C., Brechin, E. K. & Christou, G. (2002). J. Am. Chem. Soc. 124, 3725–3736. Bruker (2006). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Burla, M. C., Caliandro, R., Camalli, M., Carrozzini, B., Cascarano, G. L., De Caro, L., Giacovazzo, C., Polidori, G. & Spagna, R. (2005). J. Appl. Cryst. 38, 381–388. Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Kong, L.-Q., Ju, X.-P. & Li, D.-C. (2009). Acta Cryst. E65, m1518. Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457. metal-organic compounds Acta Cryst. (2013). E69, m439–m440 doi:10.1107/S1600536813018321 Zeghouan et al. m439 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368