HEDP Na2 is organic phosphonic acid corrosion inhibitor. It has two appearances, colourless to pale yellow transparent liquid and white powder. White powder HEDP Na2 (Etidronate Disodium), its melting point is 198°C – 199°C. It is soluble in water and ethanol and has strong moisture absorption.

CAS No.7414 83 7

Molecular Formula: C2H8O7P2Na2

Molecular Weight: 250

Etidronate Disodium Sructural Formula

HEDP 2Na, disodium salt of 1-hydroxy ethylidene-1 1-diphosphonic acid, HEDP Na2

Etidronate Disodium, HEDP Na2


HEDP Na2 has good scale and corrosion inhibition effects even under 250℃. It can dissolve the oxidized materials. HEDP Na2 is stable at high pH value. It is not easy to be hydrolyzed and to be decomposed under normal light and heat condition. HEDP Na2 acid/alkaline and chloride oxidation tolerance are better than that of other organic phosphonic acids.

HEDP Na2 can form six-ring chelating compounds with metal ions in a water system, Ca2+ in particular. This product also has good obvious dissolution threshold effects. When used with other water treatment agents, its synergistic effects are better.

HEDP Na2 is known in the market as an organo-phosphonic acid corrosion inhibitor. HEDP Na2 can chelate with Fe, Cu, and Zn ions. HEDP Na2 (Etidronate Disodium) with chelation value 270 is a good substitute for EDTA disodium powder.

Item Index
Appearance colourless to yellowish transparent liquid white powder
Active content (HEDP) % ≥ 16.5 74.0 – 79.0
Active content (HEDP Na2) % ≥ 20 ≥ 89.8
Phosphoric acid (as PO33- )% ≤ 3
Dry weight loss % 3 – 6
pH (1% solution) 4.0 – 6.0 4.0 – 6.0
Density (20℃) g/cm3 1.12-1.22
Fe,mg/L ≤ 35
Moisture % 3.0 – 6.0


  • Used as corrosion inhibitor & chelating agent in circulating cool water system

  • Used as corrosion inhibitor medium and low-pressure boiler

  • Used as corrosion inhibitor oil field water pipelines

  • Used as detergent for metal and nonmetal in light woven industry

  • Used as peroxide stabilizer and dye-fixing agent in dyeing industry

  • Used as chelating agent in non-cyanide electroplating

Packing& Storage


Different HEDP Na2, Different Pack.


HEDP Na2  liquid: 200L plastic drum,IBC(1000L).

HEDP Na2 powder: 25kg/bag.

All above can be packed as customers’ requirements.


Ten months in room shady and dry place.

Safety Protection

Attention!Avoid HEDP Na2 (Etidronate Disodium) contacts with eye and skin. Once happened, flush there with water.

HEDP Na2 Quotation.

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Except information mentioned above, you will also get the HEDP Na2 SDS. You can see it on this page - SDS Download.
HEDP Na2 Quotation.