Poly[μ(5)-{hydrogen bis­[(E)-cinnamato]}-caesium]

In the structure of the title polymeric complex, [Cs(C(9)H(7)O(2))(C(9)H(8)O(2))](n), a caesium salt of trans-cinnamic acid, the Cs(+) ions of the two individual irregular CsO(8) coordination polyhedra lie on twofold rotation axes and are linked by four bridging carboxyl O-atom donors from two cinnamate ligand species. These two ligand components are inter­linked through a delocalized H atom within a short O⋯H⋯O hydrogen bond. Structure extension gives a two-dimensional coordination polymer which lies parallel to (001). The structure was determined from a crystal twinned by non-merohedry, with a twin component ratio of approximately 1:1.