Phosphate Esters & Derivatives Available — Bulk Only

Etidronic Acid, Disodium Salt (HEDP·Na2, Disodium Etidronate)

HEDP
CAS 7417-83-6

The disodium salt of a phosphonate chelant, used to sequester metal ions and control scale and corrosion in water systems. The HEDP/etidronate class functions as a sequestering and chelating agent and as a scale and corrosion inhibitor in water-treatment programs, and serves as a chelant in cleaning formulations.

Request SDS
HS Code
2931.49
At a Glance
Material Family
Phosphate Esters & Derivatives
Record Type
Pure compound
Primary Role
Chelation / Sequestration · Scale Inhibition
Industries Served
Applications & Use Cases
  • Chelating agent: Sequesters calcium, iron, and other polyvalent metal ions.
  • Scale inhibitor: Controls mineral scale in recirculating and boiler water.
  • Corrosion inhibitor: Protects metal surfaces in water-treatment systems.
  • Detergent chelant: Stabilizes formulations against metal-ion interference.
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

Request SDS →
HS / Tariff Classification
Harmonized System (HS) Code — 6-digit international heading
2931 . 49
Chapter 29
Organic chemicals
Heading 29.31
Internationally harmonized (WCO HS)
Subheading 2931.49
6-digit international code — national tariff line adds further digits
Chemical Identity
CAS Number
7417-83-6
Full Description

Etidronic Acid, Disodium Salt (CAS 7417-83-6) is the disodium salt of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), an organophosphonate. The HEDP/etidronate class functions as a sequestering and chelating agent and as a scale and corrosion inhibitor in water-treatment programs, and serves as a chelant in cleaning formulations.

Frequently Asked Questions

What is diphosphonic acid (HEDP.Na2) used for?

Etidronic acid disodium salt (HEDP.Na2, CAS 7417-83-6) is an organophosphonate used as a sequestering and chelating agent and as a scale and corrosion inhibitor in water-treatment programs. It binds calcium, iron, and other polyvalent metal ions and is used as a chelant in cleaning formulations. RawSource supplies it in bulk for water-treatment and industrial-cleaning manufacturers.

What is another name for etidronic acid?

Etidronic acid is also known as 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) and as hydroxyethylidene diphosphonic acid. This product is its disodium salt (HEDP.Na2). Confirm whether your specification calls for the free acid or the di-/tetra-sodium salt, as the CAS and active basis differ.

What is the difference between the disodium and tetrasodium salt of HEDP?

Both derive from the same HEDP phosphonate backbone but differ in degree of neutralization — the disodium salt (this product, CAS 7417-83-6) versus the tetrasodium salt, which is more fully neutralized and carries a different CAS and pH profile. Choose the salt that matches your formulation pH and chelation target, and verify the CAS on the CoA.

Is HEDP disodium hazardous to ship?

RawSource provides a current SDS with GHS classification and DOT information for each shipment; review it for handling and transport requirements specific to the supplied grade. This context does not carry a UN number for this product, so confirm transport status against the SDS before booking freight.

What is the cost of bulk HEDP disodium salt?

Pricing is quoted by order based on active concentration, volume, packaging (drum, tote, IBC), and freight. Send RawSource your target quantity and destination for a landed quote and lead time. Cost tracks phosphonate feedstock and order scale, so we quote rather than list.

Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.