4H-1-Benzopyran-2-carboxylic acid, 5,5'-((2-hydroxy-1,3-propanediyl)bis(oxy))bis(4-oxo-, disodium salt)
5,5'-[(2-Hydroxy-1,3-propanediyl)bis(oxy)]bis[4-oxo-4H-1-benzopyran-2-carboxylic Acid], Disodium Salt