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Element 5 - Boron (B) sound

From borax and carbon; discovered 1808. A nonmetal, born is best known in borax (sodium borate) and in boric acid--the one acid that is good for the eyes. About a million tons of boron are used in industry each year. In agriculture it serves as both a plant food and a weed killer.

Properties

Atomic Number: 5
Atomic Weight: 10.811
Electron Configuration (at ground state): 1s22s22p1
Oxidation States (Bold most stable): +3
Boiling Point (K): 4275
Melting Point (K): 2365
Density (at 300K -- g/cm3): 2.34
Atomic Volume (at 300K -- cm3/mol) 4.60
Number of stable isotopes: 2
Covalent Radius (Å): 0.82
Atomic Radius (Å): 0.98
First Ionization Potential (V): 8.298
Electronegativity (Pauling's): 2.04
Specific Heat Capacity (at 300K -- J g-1 K-1): 1.026
Heat of Vaporization (kJ/mol): 507.8
Heat of Fusion (kJ/mol): 22.6
Electrical Conductivity (at 293K for polycrystalline material -- 106 (ohms)-1 cm-1): 5 x 10-12
Thermal Conductivity (at 300K -- W m-1 K-1): 27.0
Crystal Structure: Rhombohedral
Acid-Base Properties: Slightly acidic