Synthesis, crystal structure and thermal properties of catena-poly[[[bis-(2,3-di-methyl-pyrazine-κN 1)cadmium(II)]-di-μ-chlorido] monohydrate].

The title compound, {[CdCl2(C6H8N2)2]·H2O} n (C6H8N2 = 2,3-di-methyl-pyrazine) was prepared by the reaction of cadmium chloride with 2,3-di-methyl-pyrazine in water. The asymmetric unit consists of two crystallographically independent cadmium cations that are situated on a twofold rotation axis, two crystallographically independent chloride anions and 2,3-di-methyl-pyrazine ligands as well as one water mol-ecule that are all located in general positions. The cadmium cations are octa-hedrally coordinated by two terminally N-bonded 2,3-di-methyl-pyrazine ligands and four chloride anions and are linked by pairs of μ-1,1 bridging chloride anions into chains that propagate in the crystallographic b-axis direction. These chains are connected into layers via the water mol-ecule of crystallization by inter-chain O-H⋯N hydrogen bonding. Powder X-ray diffraction (PXRD) indicates that a pure phase has been obtained. Thermogravimetry (TG) coupled to differential thermal analysis (DTA) indicates that the water mol-ecules are removed in the first step and that the 2,3-di-methyl-pyrazine ligands are lost in the subsequent two steps, leading to a compound with the composition [CdCl2(C6H8N2)].