SODIUM BORATE- ▸ Glass and ceramics: Flux and raw material for borosilicate glass, glazes, and frits.
- ▸ Cleaning chemistry: Detergent builder and water-softening or buffering additive.
- ▸ Flame retardant: Flame-retardant additive for cellulosic and other substrates.
- ▸ Buffering and chelating: pH buffer and chelating agent in industrial formulations.
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.
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Sodium tetraborate decahydrate (borax) is a hydrated sodium borate used as a boron source and flux across glass, ceramics, metallurgy and industrial formulations. Identity: CAS 1303-96-4.
What it is
Sodium tetraborate decahydrate (CAS 1303-96-4), commonly called borax, is a hydrated sodium borate supplied here as ACS reagent-grade crystals. It is a convenient, water-soluble boron and alkali source.
Industrial uses
It is used as a flux in metallurgy, welding, brazing and soldering (dissolving metal oxides), a boron source and melt aid in glass and fiberglass and in ceramic glazes and frits, a buffer and alkalinity source, a detergent and cleaning-formulation builder, and a building block for other borates and boron chemicals.
Related boron compounds: boric acid and zinc borate.
Forms, grades and handling
Borax is supplied as crystalline decahydrate (and other hydrate grades) in bags and bulk; specify hydrate/grade. Boron compounds are regulated in some uses and jurisdictions; confirm regulatory status. Properties are typical reference values; the Certificate of Analysis (CoA) for the lot you buy governs. Always consult the current Safety Data Sheet (SDS) before handling, and confirm regulatory status and suitability for your application and jurisdiction. Each lot ships with CoA, TDS and SDS.
Bulk supply and RFQ
RawSource sources Sodium Tetraborate Decahydrate direct from producers in bulk, with CoA, TDS and SDS per lot. Tell us the grade, particle size or specification and quantity you need, and we will quote it. Products are sold for industrial and professional use.
Typical Properties
Typical reference values, not a specification; the Certificate of Analysis (CoA) for the lot governs.
| Property | Typical Value |
|---|---|
| Chemical / class | Inorganic borate |
| CAS Number | 1303-96-4 |
| Molecular Formula | B4H20Na2O17 |
| Molecular Weight | 381.4 g/mol |
| Handling | Refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 215-540-4
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Regulatory restriction status
Sodium Tetraborate Decahydrate (Borax) (CAS 1303-96-4) appears on the regulatory list(s) below. This is public regulatory information about the substance — not a statement about any specific supplier’s material, and not a safety claim. Confirm the current status for your jurisdiction and intended use.
- REACH SVHC Candidate List (EU): listed 18 Jun 2010 on the basis of toxic for reproduction (Art. 57(c)). SVHC status triggers EU supplier-communication and notification duties above 0.1% w/w; it is not, by itself, a ban on sale.
Sources: ECHA Candidate List / Annex XIV / Annex XVII (echa.europa.eu); U.S. EPA TSCA; UN Stockholm Convention / EU POPs Regulation; California OEHHA Proposition 65 list. Retrieved 2026-07-13.
Frequently Asked Questions
What is borax used for industrially?
Borax (sodium tetraborate decahydrate, CAS 1303-96-4) is used as a metallurgical/welding/brazing flux, a boron source and melt aid in glass, fiberglass and ceramic glazes, a buffer/alkalinity source, a detergent builder, and a building block for other borates. RawSource supplies it for industrial use.
What is the difference between borax and boric acid?
Borax is the alkaline sodium borate salt (a flux and alkali/boron source); boric acid is the weak acid form. Both are boron sources but differ in pH and solubility — choose by the chemistry your process needs.
How is bulk borax supplied and quoted?
RawSource supplies borax in bulk with CoA, TDS and SDS per lot. Pricing is quote-based on grade, particle size/specification and volume; submit an RFQ with your application and quantity.
What is the REACH and TSCA regulatory status of Sodium Tetraborate Decahydrate (Borax)?
Sodium Tetraborate Decahydrate (Borax) (CAS 1303-96-4) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 215-540-4).