Boron

Boron (B)

Atomic Number: 5
Atomic Weight: 10.81
Melting Point: 2300
Boiling Point: 2550
Specific Gravity: 2.34 (crystals) 2.37 (amorphous)
Valence(s): 3
Boron was discovered in 1808 by Davy, Gay-Lussac, and Thenard. Rasorite is the main mineral source of boron. Impure boron is a dark brown powder that turns bright green when ignited; this makes it useful in pyrotechnics. Appliances such as dryers and refrigerators are coated with boron compounds. [LM] {RW}