Cas No: 2809-21-4          
EINESC No: 220-552-8
Molecular weight: 206,03 g/mol  

Chemical Formula: C2H8O7P2
Chemical Structure:

Physical Properties

General Properties: Pale yellow, colorless solution

Odor: odorless


Boiling point:

Melting point: – 25 °C

Flash point:

Vapor pressure:

Refraction index:

Solubility (aqueous) completely miscible


General Properties

Hydroxyethylene diphosphonic acid, or HEDP, is an odorless organic phosphonate. It is a good chelation agent and it is very effective againts calcium, iron, copper and zinc ions. It yields good results when it is used in water purification facilities. It maintains its stability in presence of chlorine. It can also dissolve oxidation on metal surfaces. It is a good lime and corrosion blocker. It demonstrates good stability in high pH values. It has better tolerance than other organic phosphates in these fields.


HEDP is prepared by reaction of phosphor trichlorine and acetic acid or reaction of phosphor acid and acetic acid/acetic anhydrate mixture.


HEDP has a wide range of uses. It is used againts osteolysis in medical fields. It improves bone structure by stabilizing absorption. It also prevents calcification.

It is also used in water cooling and water purificaton systems. It is also used as corrosion blocker in these fields. It is used as industrial detergent in swimming pools. It is also a good corrosion blocker in metal surface processes. It also works as auxiliary agent in textile business.

Safety Measures and Toxic Values

HEDP is dangerous if it is swallowed. It may cause injuries in skin and eyes.