catena-Poly[[bis-(nitrato-κ(2) O,O')barium]-bis-(μ-l-histidine-κ(3) O,O':O].

In the polymeric title compound, [Ba(NO3)2(C6H9N3O2)2] n , the Ba(II) atom is located on a crystallographic twofold axis and is coordinated by ten O atoms. Six are derived from two zwitterionic l-histidine mol-ecules that simultaneously chelate one Ba(II) atom and bridge to another. The remaining four O atoms are derived from two chelating nitrates. The mol-ecules assemble to form a chain along [010]. In the crystal, chains are linked via N-H⋯O and N-H⋯N hydrogen bonds, generating a three-dimensional network.