HEDP is a sequestering, anti-scaling, and phosphonic acid chelating agent that has a hydrolytic stability. HEDP Disodium Salt is manufactured from acetic anhydride and phosphorus Trichloride or phosphorus acid. If phosphorus trichloride is used, then it is first converted into the phosphorus acid within the reaction vessel and only then reacts with the other essential raw material- acetic anhydride. Also called 1-Hydroxyethylidene-1,1- Diphosphonic Acid, Disodium Salt, the HEDP Disodium Salt in white powder form has a molecular formula of C2H6O7P2Na2, molecular weight of 250.0, and pH of 4.5 To 6.5. It is mostly packed in HDPE bags. It has many uses in chemical industry, electric power industry, metallurgy industry, light woven industry and dyeing industry.