The title compound, {(C4H12N2)[Bi2(C7H3NO4)4(H2O)]- H2O}n or {(pipzH2)[Bi2(pydc)4(H2O)]H2O}n, where pydcH2 is pyridine-2,6-dicarboxylic acid and pipz is piperazine, was obtained by reaction of Bi(NO3)35H2O with (pipzH2)(pydc- H)23H2O in a 1:2 molar ratio in aqueous solution. There are two independent BiIII atoms in the structure, one of which is eight-coordinate with a distorted bicapped trigonal-prismatic geometry, and another which is nine-coordinate with a distorted tricapped trigonal-prismatic geometry. The carboxylate groups of the (pydc)2 ligands link dinuclear [Bi2(C7H3NO4)4(H2O)]2 units into one-dimensional coordination polymers. The pipzH2 2+ cations (site symmetry 1) and non-coordinated water molecules lie between these polymers, forming N—H O and O—H O hydrogen bonds to the O atoms of the carboxylate groups.
