Synthesis and crystal structure of catena-poly[cobalt(II)-di-μ-chlorido-μ-pyridazine-κ(2) N (1):N (2)]

The reaction of cobalt dichloride hexa­hydrate with pyridazine leads to the formation of crystals of the title compound, [CoCl(2)(C(4)H(4)N(2))]( n ). This compound is isotypic to a number of compounds with other divalent metal ions. Its asymmetric unit consists of a Co(2+) atom (site symmetry 2/m), a chloride ion (site symmetry m) and a pyridazine mol­ecule (all atoms with site symmetry m). The Co(2+) cations are coordinated by four chloride anions and two pyridazine ligands, generating trans-CoN(4)Cl(2) octa­hedra, and are linked into [010] chains by pairs of μ-1,1-bridging chloride anions and bridging pyridazine ligands. In the crystal structure, the pyridazine ligands of neighboring chains are stacked onto each other, indicating π–π inter­actions. Powder X-ray diffraction proves that a pure crystalline phase was obtained. Differential thermonalysis coupled to thermogravimetry (DTA–TG) reveal that decomposition is observed at about 710 K. Magnetic measurements indicate low-temperature metamagnetic behavior as already observed in a related compound.