|Atomic mass||10.811 amu|
Boron was discovered in 1808 and large-scale mining of borax took place during the 1880s in Death Valley, California. Since then, principal boron ores are found in evaporated lake beds in the southwestern United States in the form of borax, Na2B4O5(OH)4·8H2O.
Pure boron is a crystalline, high-melting substance having very low electrical and thermal conductivity. It is almost as hard as diamond.
Boron and its compounds are widely used. These include:
- Borax, which is a slightly alkaline compound, is added to laundry detergents for pH control.
- Sodium perborate (NaBO3) is a mild but effective bleach (Clorox II).
- Trace amounts of boron is required for plant growth. Its salt is mixed with superphosphate and are applied to the soils.
- Boron nitride and boron carbide are used as abrasives.
- Boron is used in soldering and welding as a flux it can dissolve metal oxide films.
- Dilute boric acid are used as mild antiseptics and antifungal agents.
- Boric oxide is a raw material used in the manufacture of glass. Pyrex glassware is a type of borosilicate glass in which some of the sodium and calcium are replaced by boron.
- Alloys and polymers used in jet engines are strengthened by the addition of fibres of elemental boron.
- Boron or cadmium-containing control rods in nuclear reactors are used to absorb neutrons to control the chain reaction to proceed at a steady rate.