BORIC ACID- ▸ Glass and glass fiber: Boron source for borosilicate glass and fiberglass.
- ▸ Metallurgical flux: Flux for soldering and brazing.
- ▸ Flame retardant: Treats cellulose insulation and textiles.
- ▸ Wood preservation: Used to protect and weatherproof wood.
- ▸ Electroplating: Buffer additive for nickel plating baths.
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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Boric acid (orthoboric acid) is a versatile inorganic boron source used across glass, ceramics, metallurgy, wood treatment and flame-retardant and industrial formulations. Identity: CAS 10043-35-3.
What it is
Boric acid (CAS 10043-35-3, H3BO3) is a white crystalline weak inorganic acid and the most common industrial boron source. It is mild, water-soluble on warming, and easy to handle.
Industrial uses
It is used in borosilicate and fiberglass manufacture (a boron source that lowers thermal expansion), ceramic frits and glazes, metallurgical fluxes and electroplating, wood-treatment and cellulosic flame-retardant formulations, and as a buffer and pH control agent and a boron source in micronutrient and industrial formulations. It is also a building block for other borates.
Related boron flame retardant: zinc borate; see the flame retardants guide.
Forms, grades and handling
Boric acid is supplied as crystalline powder or granules in bags and bulk. Boron compounds are subject to regulation in some uses and jurisdictions; confirm regulatory status for your application. 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 Boric Acid 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 boron compound |
| CAS Number | 10043-35-3 |
| Molecular Formula | BH3O3 |
| Molecular Weight | 61.84 g/mol |
| Handling | Refer to the current SDS |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 233-139-2
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Solutions Using This Product
Process-solution guides on this site that specify this chemistry:
- Flame Retardants for Textiles: APP, Mineral & N-P Systems (Textiles)
- Metalworking Fluid Biocides, pH Amines & Buffers (Industrial Manufacturing)
- Hydraulic Fracturing Chemicals (Friction Reducers & Gels) (Oil, Gas & Mining)
Frequently Asked Questions
What is boric acid used for industrially?
Boric acid (CAS 10043-35-3) is used as a boron source in borosilicate and fiberglass manufacture, ceramic frits and glazes, metallurgical fluxes and electroplating, wood-treatment and cellulosic flame-retardant formulations, and as a buffer/pH agent. RawSource supplies it for industrial use.
Is boric acid a flame retardant?
Boric acid and other borates are used in cellulosic and wood flame-retardant treatments, promoting char and a protective glassy layer; confirm regulatory status for your application.
How is bulk boric acid supplied and quoted?
RawSource supplies boric acid 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 Boric Acid (Orthoboric Acid)?
Boric Acid (Orthoboric Acid) (CAS 10043-35-3) 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 233-139-2).