Crystal structure of poly[[aqua(μ₂-pyrazine-κ² <i>N</i>:<i>N</i>′)(μ₂-2,3,5,6-tetrachlorobenzene-1,4-dicarboxylato-κ² <i>O</i> ¹:<i>O</i> ⁴)copper(II)] hemihydrate]

The asymmetric unit of the title compound, {[Cu₂(C₈Cl₄O₄)₂(C₄H₄N₂)₂(H₂O)₂]·H₂O} _<i>n</i> or {[Cu₂(Cl₄bdc)₂(pyz)₂(H₂O)₂]·H₂O} _<i>n</i> comprises of a Cu^II ion, one tetra-chloro-benzene-dicarboxyl-ate ion (Cl₄bdc^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 CuN₂O₃ coordination environment comprising two oxygen atoms of the Cl₄bdc^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 Cl₄bdc^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.