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What Is the Chemical Makeup of Borax?

Borax is a mineral found in dry lakes. It is a deposit of boron which forms after the evaporation of water. It has many commercial uses, especially as a cleaning agent.

Chemistry
- Borax is hydrated sodium borate. The chemical formula is Na2B4O7-10H2O. The structure is composed of interlocking chains of BO2(OH) triangles and BO3(OH) tetrahedrons bound to sodium and water octahedron.
Description
- Borax is white to clear with a glassy luster. Light can pass through or become diffuse upon contact with borax. It produces a white streak.
Dehydration Reaction
- Borax can convert to a mineral called tincalconite, which has a chemical formula of Na2B4O7-5H2O. The difference is a loss of water. It has a chalky white appearance, but retains the crystal structure of borax.
Formation
- Temporary lakes which form from mountain runoffs are rich in boron. As the water evaporates, the concentration of boron increases to the point where crystals begin to form.
Applications
- Borax is used to wash, deodorize and freshen laundry, to clean the bathroom shower, tub and tile and to soften water.

Rocks & Minerals