Poly[[μ(2)-aqua-μ(3)-(4-carb-oxy-2-propyl-1H-imidazole-5-carboxyl-ato-κN,O:O:O)-sodium] hemihydrate].

In the title compound, {[Na(C(8)H(9)N(2)O(4))(H(2)O)]·0.5H(2)O}(n), the Na(+) ion is coordinated by two bridging water mol-ecules, one N atom and three O atoms from three 4-carb-oxy-2-propyl-1H-imidazole-5-carboxyl-ate (H(2)pimdc) ligands. Adjacent Na(+) ions are linked alternately by two water O atoms and two carb-oxy O atoms into a chain along [001]. These chains are connected through the coordination of the carboxyl-ate O atoms to the Na(+) ions, forming a three-dimensional structure. An intra-molecular O-H⋯O hydrogen bond and inter-molecular N-H⋯O and O-H⋯O hydrogen bonds are present in the crystal structure.