FACULTY OF CHEMICAL TECHNOLOGY IN SPLIT
PERIODIC TABLE OF THE ELEMENTS version 1.7
B
English: Boron
French: Bore
Croatian: Bor
German: Bor
Italian: Boro
Atomic number: 5
Group numbers: 13
Period: 2
Standard state (20 °C): solid
Boron compounds have been known for thousands of years, but the element was not discovered until 1808 by Sir Humphry Davy (England) and independently by Joseph-Louis Gay-Lussac (France) and L. J. Thenard (France). The origin of the name comes from the Arabic word buraq and the Persian word burah meaning boraks (Na2B4O7×10H2O). It is hard, brittle, lustrous black semimetal. Unreactive with oxygen, water, alkalis or acids. Combines with most metals to form borides.
Electronic configuration: [He] 2s2 2p1
Relative atomic mass: 10.811(7)
Formal oxidation number: +3
Electronegativities: 2.04
Thermal conductivity: 27 W/(m K)
Electrical resistivity (20 °C): 1.8E+12 μΩcm
Atomic radius: 79.5 pm
Density (g/dm3): 2340 (beta, 293 K)
Molar volume (cm3/mol): 4.62 (beta, 293 K)
Melting point: 2075 °C
Boiling point: 4000 °C
Critical temperature: 3011 °C
Heat of fusion: 22.2 kJ/mol
Heat of vaporization: 504.5 kJ/mol
Heat of atomization: 557.64 kJ/mol
Boron is obtained from kernite, a kind of borax (Na2B4O7.10H2O). High purity boron is produced by electrolysis of molten potassium fluroborate and potassium chloride (KCl). Amorphous boron is used in pyrotechnic flares to provide a distinctive green color and in rockets as an igniter. The price of 99.5 % pure boron pieces is 997.90 € for 250 g.
4Be <= 5B => 6C
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Periodic Table of the Elements
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Last modified:
29.03.2003
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