Boron

Symbol: B
Atomic Number: 5
Atomic Weight: 10.811
Element Classification: Semimetallic
Discovered By: Sir H. Davy, J.L. Gay-Lussac, L.J. Thenard
Discovery Date: 1808 (England/France)
Name Origin: The Arabic and Persian words for borax.

Density (g/cc): 2.34
Melting Point (K): 2573
Boiling Point (K): 3931
Appearance: Hard, brittle, lustrous black semimetal
Atomic Radius (pm): 98
Atomic Volume (cc/mol): 4.6
Covalent Radius (pm): 82
Ionic Radius: 23 (+3e)
Specific Heat (@20C J/g mol): 1.025
Fusion Heat (kJ/mol): 23.60
Evaporation Heat (kJ/mol): 504.5
Thermal Conductivity (@25C W/m K):
Debye Temperature (K): 1250.00
Pauling Negativity Number: 2.04
First Ionizing Energy (kJ/mol): 800.2
Oxidation States: 3
Electronic Configuration: [He] 2s2 2p1
Lattice Structure: Tetragonal (TET)
Lattice Constant (): 8.730
Lattice C/A Ratio: 0.576

Mineral Hardness [no units]: 9.3
Vickers Hardness [/MN m-2]: 49000

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