Lindsay S

BORON

Basic Information  

Name: Boron
Symbol: B
Atomic Number: 5
Atomic Mass: 10.811 amu
Melting Point: 2300.0 °C (2573.15 °K, 4172.0 °F)
Boiling Point: 2550.0 °C (2823.15 °K, 4622.0 °F)
Number of Protons/Electrons: 5
Number of Neutrons: 6                                                                                                                                                        
Classification: Metalloid
Crystal Structure: Rhombohedral
Density @ 293 K: 2.34 g/cm³ 
Color: brownish

                                   Facts

Date of Discovery: 1808
Discoverer: Sir Humphry Davy, J.L Gay-Lussac          
Name Origin: From borax and carbon
Uses: heat resistant alloys
Obtained From: kernite

It is not normally necessary to make boron in the laboratory and it would normally be purchased as it is available commercially. The most common sources of boron are tourmaline, borax [Na₂B₄O₅(OH)₄.8H₂O], and kernite [Na₂B₄O₅(OH)₄.2H₂O]. It is difficult to obtain pure. It can be made through the magnesium reduction of the oxide, B₂O₃. The oxide is made by melting boric acid, B(OH)₃, which in turn is obtained from borax.

B₂O₃ + 3Mg 2B + 3MgO

Samm amounts of high purity boron are available through the thermal decomposition of compounds such as BBr₃ with hydrogen gas using a heated tantalum wire. Results are better with hot wires at temperatures over 1000°C.

LINKS:

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                BORON