Borax Decahydrate


Multifunctional boric oxide source

20 Mule Team® borax decahydrate is the refined form of natural sodium borate. Composed of boric oxide (B2O3), sodium oxide, and water, this mild alkaline salt has excellent buffering and fluxing properties.

Borax Decahydrate

Na2B4O· 10H2O
Sodium Tetraborate Decahydrate

Made In

USA and France

What can U.S. Borax’s borax decahydrate do for you? 

Available in a white crystalline powder or granular form, our borax decahydrate is an important multifunctional source of boric oxide, particularly for processes in which the simultaneous presence of sodium is beneficial.

Borax decahydrate is a trusted cleaning agent

Gentle on skin and tough on dirt and oils, the inherent characteristics of borax decahydrate make it essential in industrial cleaning products, such as polishes, waxes, hard surface cleaners, and institutional cleaning compounds. Borax decahydrate is a:

  • pH buffering agent
  • Enzyme stabilizer
  • Emulsifier of oils, waxes, and paraffins
  • Gentle abrasive
  • Remover for medium-to-heavy soils—such as those encountered in industrial operations
  • Water softener
  • Alkaline booster

Borax decahydrate provides protective properties

Our borax decahydrate can also be used to:
  • Dissolve metal oxides in scrap metal recovery and slag smelting
  • Act as a cover flux to prevent oxidation at the surface of molten ingot
  • Exclude air and prevent oxidation in welding, brazing, and soldering
  • Slow corrosion in aqueous systems, water treatment chemicals, and automotive and engine coolant formulations
  • Neutralize acidic residue that results from ethylene glycol decomposition and minimize the rate of oxidation at the surface of metal

Borax decahydrate enhances formulations in a range of applications

Because our borax decahydrate is highly soluble in ethylene glycol, it is especially useful in car antifreeze formulations. In addition, it can also be used as a flame retardant for cellulosic materials, a buffer and catalyst for organic dyes, a carrier for herbicides, and a degreasing buffer in enameling processes. Borax decahydrate:

  • Works with boric acid as a gentle cleanser and buffering agent in contact lens solutions
  • Replaces chromates in railroad and other diesel engine coolants
  • Stabilizes and acts as a bonding agent in specialty abrasives
  • Provides an intermediate-temperature glassy bond before the establishment of the ceramic bond
  • Improves tack and green strength in casein- and dextrin-based adhesives by cross linking conjugated hydroxyl groups
  • Neutralizes residual acid from the pickling stage in wire drawing; the deposit of the salt remaining on the wire is valuable as a carrier of dry powdered lubricant


We’re here to help with your boron needs. 

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Chemical and Physical Properties

Molecular weight: 381.37

Specific gravity: 1.71

Appearance: Free-flowing, white, crystalline product

Melting point: 743°C (1369°F), starts losing water at 62°C (144°F) in an enclosed space

Solubility: 5.93% by weight in saturated solution at room temperature

Stability: Chemically stable under normal conditions; avoid temperature and humidity fluctuations and prevent damage to packaging

Bulk density: 48 lb/ft3 (769 kg/m3)

Angle of repose: 35°

Chemical Composition (Theoretical)

Boric oxide, B2O3: 36.51%

Sodium oxide, Na2O: 16.25%

Water of crystallization, H2O: 47.24%

Anhydrous equivalent, NaBO2: 52.76%

Containers: Products may be available in bulk, IBCs, or small bags

Among the sodium borates, borax decahydrate shows the greatest tendency to cake. However, it can be successfully shipped and handled in bulk if proper precautions are taken.

Borax decahydrate TG has a No. 8 U.S. sieve specification, with a mesh size of 2.36 mm and a retained guarantee of 0.1% or less. These specifications, as well as the product’s chemical properties, are determined by U.S. Borax analytical methods.

Dissolved in water, borax decahydrate hydrolyzes, producing a mildly alkaline solution that can neutralize acids. It also combines with strong alkalis to form compounds of lower pH. The relatively constant pH of borax decahydrate solutions makes it an excellent buffering agent.

Borax decahydrate is chemically stable under normal storage conditions, although it will slowly lose water of crystallization if exposed to a warm, dry atmosphere. For borax decahydrate EP, NF, and SP grades we recommend NOT storing in a controlled atmosphere below 60% of relative humidity. Conversely, exposure to a humid atmosphere can cause caking. When storing the product, avoid wide fluctuations in temperature and humidity and ensure that the packaging is not damaged.

The product’s solubility in water; solubility in solvents such as glycerol, ethylene glycol, methanol, and acetone; and the product’s pH as compared to that of common alkalis can be found in the product data sheet.


Contact our sample fullfillment team.

We’re here to help with your boron needs.

Contact sales

Our regional sales teams are ready to help with your purchase

Learn More

Get technical support


Your resource for borate-related technical and laboratory services across every industry

Learn More

Request a sample

Get small quantities of our products to ensure you have what you need for your formulation or process

Learn More

Borax Decahydrate in Action

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U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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