Crystal structure of poly[[aqua-(μ(2)-pyrazine-κ(2) N:N')(μ(2)-2,3,5,6-tetra-chloro-benzene-1,4-di-car-boxyl-ato-κ(2) O (1):O (4))copper(II)] hemihydrate].

The asymmetric unit of the title compound, {[Cu(2)(C(8)Cl(4)O(4))(2)(C(4)H(4)N(2))(2)(H(2)O)(2)]·H(2)O} (n) or {[Cu(2)(Cl(4)bdc)(2)(pyz)(2)(H(2)O)(2)]·H(2)O} (n) comprises of a Cu(II) ion, one tetra-chloro-benzene-dicarboxyl-ate ion (Cl(4)bdc(2-)), one pyrazine ligand (pyz), and one and a half water mol-ecules. The Cu(II) ion exhibits a five-coordinated square-pyramidal geometry with a CuN(2)O(3) coordination environment comprising two oxygen atoms of the Cl(4)bdc(2-) ligands, one oxygen atom of a water mol-ecule, and two nitro-gen atoms of the pyz ligands. The carboxyl-ate group is almost perpendicular to the benzene ring and shows monodentate coordination to the Cu(II) ion. The Cu(II) ions of these units are bridged by both the Cl(4)bdc(2-) and pyz ligands to form two-dimensional (2D) layers, which are linked by alternating hydrogen-bonding and C-Cl⋯π inter-actions to yield a three-dimensional network.