Poly[[Diaquadi-Mu(2)-Cyanido-Bis(Mu(2)-Pyrazine-2-Carboxylato)Dicopper(I )Copper(Ii)] Dihydrate]

In the title compound, {[(CuCu2I)-Cu-II(C5H3N2O2)(2)(CN)(2)(H2O)2]2H(2)O}(n), the Cu-II atom lies on an inversion centre and is octahedrally coordinated by two N atoms and two O atoms from opposing pyrazine-2-carboxylate (2-pac) ligands and two water O atoms. The Cu-I atom has a triangular geometry, coordinated by one N atom and one C atom from two bridging cyanide ligands, and another N atom from the 2-pac ligand. The three-dimensional structure features a succession of two-dimensional sheets containing [Cu(CN)](n) chains linked by Cu(2-pac)(2)(H2O)(2) groups. The coordinated and free water molecules are involved in an extended three-dimensional hydrogen-bond network with the 2-pac ligands.