A new packing variant of catena-poly[[aquachlorocopper(II)]-mu-pyrazine-2-carboxylato-O,N:N'].

Single crystals of the title coordination polymer, [CuCl(C5H3N2O2)(H2O)], have been prepared by hydrothermal synthesis. The compound is composed of infinite one-dimensional chains of pseudo-square-pyramidal Cu(II) ions connected via pyrazine-2-carboxylate ligands. A network of O-H...O hydrogen bonding between adjacent chains is responsible for a bilayer structure different from the previously reported polymorph.