The title compound, bis( μ 2 aqua)(aqua)(3 carboxy acrylate) monosodium(Ⅰ), was synthesized in an ethanol water solution and its crystal structure was determined by means of X ray diffraction. The crystal is triclinic , space group P 1 with the cell parameters a =0 592 4(2) nm, b =0 635 7(3) nm, c =1 117 7(6) nm, α =104 18°, β =91 53°, γ =100 19°, V =0 400 6(3) nm 3, Z =2, the final R value is 0 033 5. The supramolecule is made up of coordination chains, which are further extended into a three dimensional network via the hydrogen bonding interactions. The title compound, bis (μ 2 aqua) (aqua) (3 carboxy acrylate) monosodium (I), was synthesized in an ethanol water solution and its crystal structure was determined by means of X ray diffraction. The crystal is triclinic, space group P 1 with the cell parameters a = 0 592 4 (2) nm, b = 0 635 7 (3) nm, c = 1 117 7 (6) nm, α = 104 18 °, β = 91 53 °, 100 19 °, V = 0 400 6 (3) nm 3, Z = 2, the final R value is 0 033 5. The supramolecule is made up of coordination chains, which are further extended into a three dimensional network via the hydrogen bonding interactions.