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Borax Pentahydrate

Alternate Names: Borax 5 Mol, Sodium Tetraborate, Borax 5-hydrate

Description: Etibor-48

Oxide Analysis Formula
Na2O 21.29% 1.00
B2O3 47.80% 2.00
H2O 30.90%n/a
Oxide Weight 201.20
Formula Weight 291.17


Consists of white crystalline granules or powder. It is mildly alkaline in solution. The advantages of this material vs. the decahydrate form lie in the lower transportation, handling and storage costs of a more concentrated product. 74.6 lb. of this material are equivalent to 100 lb. of decahydrate.

It is stable under ordinary conditions, free-flowing, and easily handled by air or mechanical conveying.

Borax pentahydrate is currently produced at Bandirma Borax Plant in Turkey and at Rio Tinto in California.

Related Information

The amazing fluxing power of boron (in borax)

Tap picture for full size and resolution

The two top clay bars contain 15% hydrous borax. At cone 06, a very low temperature, it has already melted and drained out of the bars, running down over the others as a glass.


Borax Pentahydrate Eitbor-48 Data Sheet
Neobor Data Sheet
Materials Anhydrous Borax
A white, odorless product crystalline granular by dehydrating Borax to remove the crystal bound water.
Materials Boric Acid
Materials Borax Decahydrate
Materials Boric Oxide
Hazards Boron Compounds and Their Toxicity
Typecodes Generic Material
Generic materials are those with no brand name. Normally they are theoretical, the chemistry portrays what a specimen would be if it had no contamination. Generic materials are helpful in educational situations where students need to study material theory (later they graduate to dealing with real world materials). They are also helpful where the chemistry of an actual material is not known. Often the accuracy of calculations is sufficient using generic materials.
Typecodes Flux Source
Materials that source Na2O, K2O, Li2O, CaO, MgO and other fluxes but are not feldspars or frits. Remember that materials can be flux sources but also perform many other roles. For example, talc is a flux in high temperature glazes, but a matting agent in low temperatures ones. It can also be a flux, a filler and an expansion increaser in bodies.
Glossary Borate
Borate glazes, those fluxed with the oxide B2O3, are the most common type used in ceramic industry and hobby for low and medium temperatures.
Oxides B2O3 - Boric Oxide
Minerals Borate Minerals
The major borate minerals are Colemanite and Ulexite. The geology required for borates is found in v
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