1-Hydroxyethylidene-1, 1-Diphosphonic Acid

• Commonly known as HEDP (60%), rarely called ADPA
• Was the 2nd generation (after ATMP) antiscalant/sequestrant developed for use in a variety of applications; has considerable resistance to degradation by chlorine
• Relative calcium intolerance (may precipitate out as the calcium phosphonate in high hardness waters)
• Applications include cooling water, oilfield, reverse osmosis, textile, swimming pool, peroxide manufacture, photochemicals and I&I compounding