General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Boron Symbol B
atomic number 5 Atomic weight 10.81
Density @ 293 K 2.34 g/cm3 Atomic volume 4.6 cm3/mol
Group Non-Metal discovered 1808


state (s, l, g) s
melting point 2352.2 K boiling point 3923.2 K
Heat of fusion 50.20 kJ/mol Heat of vaporization 489.70 kJ/mol
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1st ionization energy 800.6 kJ/mole electronegativity 2.04
2nd ionization energy 2427 kJ/mole electron affinity 26.7 kJ/mole
3rd ionization energy 3659.7 kJ/mole Specific heat 1.02 J/gK
heat atomization 573 kJ/mole atoms

Oxidation & Electrons

Shells 2,3 electron configuration [He] 2s2 2p1
minimum oxidation number 0 maximum oxidation number 3
min. common oxidation no. 0 max. common oxidation no. 3
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Appearance & Characteristics

structure special: B12 icosahedra color black
uses borax, glass making(B2O3) toxicity
hardness 9.5 mohs characteristics B12 icosahedra; 3 forms


reaction with air mild, w/ht = B2O3 reaction with 6M HCl none
reaction with 6M HCl none reaction with 15M HNO3 none
reaction with 6M NaOH none
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Other Forms

number of isotopes 2 hydride(s) B2H6 and many BxHy
oxide(s) B2O3 chloride(s) BCl3 and many BxCly


ionic radius (2- ion) pm ionic radius (1- ion) pm
atomic radius 85 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) 41 pm
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thermal conductivity 27.4 J/m-sec-deg electrical conductivity 0 1/mohm-cm
polarizability 3 A^3


source Na and Ca borates (misc) rel. abund. solar system 1.326 log
abundance earth's crust 1 log cost, pure 250 $/100g
cost, bulk $/100g
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World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.