The title compound, {[CoBr2(C5H4N 2O2)(H2O)]·H2O}n, is a one-dimensional coordination polymer which crystallizes as a monohydrate. The asymmetric unit contains one CoII atom in a distorted octa-hedral geometry, forming a chain parallel to [010] with the pyrazine carb-oxy-lic acid ligands coordinating on one side in a bidentate fashion through one N and one O atom, and in a monodentate fashion through a N atom, with N atoms trans, and with both ligands lying in the same plane. The bromide atoms are cis to each other, while a water molecule occupies the final octahedral coordination site. The chains are linked together though an O - H⋯Br hydrogen bonding network, and are further stabilized by an O - H⋯Br and O-H⋯O hydrogen-bonding framework with the solvent water molecule.
