catena-Poly[cobalt(II)-di-l-chlorido- j 4 Cl:Cl-l-1,5-dimethyl-1H-tetrazole- j 2 N 3 :N 4 ]: an X-ray powder investigation Ludmila S. Ivashkevich,* Alexander S. Lyakhov, Anastasiya P. Mosalkova, Pavel N. Gaponik and Oleg A. Ivashkevich Research Institute for Physico-Chemical Problems of Belarusian State University, Leningradskaya Street 14, Minsk 220030, Belarus Correspondence e-mail: iva@bsu.by Received 27 November 2008; accepted 23 January 2009 Key indicators: powder X-ray study; T = 295 K; mean (C–C) = 0.015 A ˚ ; R factor = 0.018; wR factor = 0.024; data-to-parameter ratio = 19.9. The asymmetric unit of the title compound, [CoCl 2 (C 3 H 6 N 4 )] n , contains two Co atoms, both lying on inversion centres, two Cl atoms and one 1,5-dimethyltetrazole ligand. The coordination polyhedra of both Co atoms adopt flattened octahedral geometry, with two N atoms from two ligands in axial positions and four Cl atoms in equatorial sites. Neighbouring Co atoms are linked together via two bridging Cl atoms and one tetrazole ring to form polymeric chains running along the a axis. Related literature For the crystal structure of a related Cu complex, see: Ivash- kevich et al. (2006). For values of radii for ions with octahedral coordination and molecular geometric parameters, see: Shannon (1976) and Allen (2002), respectively. For details of the indexing algorithm, see: Werner et al. (1985). Experimental Crystal data [CoCl 2 (C 3 H 6 N 4 )] M r = 227.95 Triclinic, P 1 a = 6.7159 (4) A ˚ b = 7.5986 (4) A ˚ c = 8.9231 (5) A ˚  = 108.639 (2)   = 107.259 (3)   = 105.769 (3)  V = 376.72 (4) A ˚ 3 Z =2 Co K radiation T = 295 K Specimen shape: flat sheet 30  30  1 mm Specimen prepared at 100 kPa Specimen prepared at 295 K Particle morphology: finely ground powder, light-violet Data collection HZG-4A (Carl Zeiss, Jena) diffractometer Specimen mounting: packed powder pellet Specimen mounted in reflection mode Scan method: step 2 min = 11.0, 2 max = 130.0  Increment in 2 = 0.02  Refinement R p = 0.018 R wp = 0.024 R exp = 0.025 R B = 0.023 S = 0.97 Wavelength of incident radiation: 1.79021 A ˚ Excluded region(s): none Profile function: psevdo-Voigt,  = 0.664(5) 896 reflections 45 parameters 7 restraints H-atom parameters constrained Preferred orientation correction: none Table 1 Selected bond lengths (A ˚ ). Co1—Cl2 2.461 (3) Co1—N4 2.224 (10) Co1—Cl1 i 2.482 (3) Co2—Cl1 2.446 (3) Co2—N3 2.111 (9) Co2—Cl2 ii 2.479 (3) Symmetry codes: (i) x  1; y; z; (ii) x þ 1; y; z. Data collection: local program; cell refinement: FULLPROF (Rodrı´guez-Carvajal, 2001); data reduction: local program; program(s) used to refine structure: FULLPROF; molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: FULLPROF, SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2003). This work was supported by the Belarusian Foundation for Fundamental Research (grant No. X08-139). Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV2491). References Allen, F. H. (2002). Acta Cryst. B58, 380–388. Ivashkevich, L. S., Lyakhov, A. S., Gaponik, P. N., Degtyarik, M. M., Ivashkevich, O. A., Tiutiunnikov, S. I. & Efimov, V. V. (2006). Acta Cryst. C62, m607–m609. Rodrı´guez-Carvajal, J. (2001). FULLPROF. CEA/Saclay, France. Shannon, R. D. (1976). Acta Cryst. A32, 751–767. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Werner, P.-E., Eriksson, L. & Westdahl, M. (1985). J. Appl. Cryst. 18, 367–370. metal-organic compounds m236 Ivashkevich et al. doi:10.1107/S1600536809003018 Acta Cryst. (2009). E65, m236 Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368