Received 4 July 2008
The structure of the title compound, C5H5N2O2+·Cl-, is composed of chloride anions and 4-carboxypyridazin-1-ium cations. Chloride anions bridge the cations via O-HCl and N-HCl hydrogen bonds to form ribbons. The latter, linked by van der Waals forces with lengths in the range 3.254 (2)-3.497 (2) Å, form coplanar layers. Very weak interactions operate also between adjacent layers, as indicated by their spacing of 3.339 (1) Å.
For the crystal structure of pyridazine-3-carboxylic acid hydrochloride, see: Gryz et al. (2003). For a report of molecular layers in the structure of pyrazine-2-carboxylic acid, see: Takusagawa et al. (1974).
Data collection: KM-4 Software (Kuma, 1996); cell refinement: KM-4 Software; data reduction: DATAPROC (Kuma, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RK2101 ).
Gryz, M., Starosta, W., Ptasiewicz-Bak, H. & Leciejewicz, J. (2003). J. Coord. Chem. 56, 1505-1511.
Kuma (1996). KM-4 Software. Kuma Diffraction Ltd, Wroclaw, Poland.
Kuma (2001). DATAPROC. Kuma Diffraction Ltd, Wroclaw, Poland.
Oxford Diffraction (2008). CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Takusagawa, F., Higuchi, T. & Shimada, A. (1974). Bull. Chem. Soc. Jpn, 47, 1409-1414.