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Periodic Table of Elements

Element Boron – B

Comprehensive data on the chemical element Boron is provided on this page; including scores of properties, element names in many languages, most known nuclides of Boron. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one studies. Using the "Periodic Table of Elements Quick Navigation" graphic at the bottom of the sidebar menu, one can quickly jump from chemical element to chemical element.

Boron Menu

• Boron Page One
  • Overview of Boron
  • Boron's Name in Other Languages
  • Atomic Structure of Boron
  • Chemical Properties of Boron
  • Physical Properties of Boron
  • Regulatory / Health
  • Who/When/Where/How
• Boron Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Boron Page Three
  • Common Chemical Compounds of Boron

Overview of Boron

• Atomic Number:5
• Group: 13
• Period: 2
• Series: Metalloids (Nonmetal)

Boron's Name in Other Languages

• Latin: Borum
• Czech: Bor
• Croatian: Bor
• French: Bore
• German: Bor - r
• Italian: Boro
• Norwegian: Bor
• Portuguese: Bóro
• Russian:
• Spanish: Boro
• Swedish: Bor

Atomic Structure of Boron

• Atomic Radius: 1.17Å
• Atomic Volume: 4.6cm³/mol
• Covalent Radius: 0.82Å
• Cross Section (Thermal Neutron Capture)_a/barns: 767
• Crystal Structure: Rhombohedral

  

• Electron Configuration:

  1s² 2s²p¹

• Electrons per Energy Level: 2,3

  Shell Model
  

• Ionic Radius: 0.23Å
• Filling Orbital: 2p¹
• Number of Electrons (with no charge): 5
• Number of Neutrons (most common/stable nuclide): 6
• Number of Protons: 5
• Oxidation States: 3
• Valence Electrons: 2s²p¹

  Electron Dot Model
  

Chemical Properties of Boron

• Electrochemical Equivalent: 0.1344g/amp-hr
• Electron Work Function: 4.45eV
• Electronegativity: 2.04 (Pauling); 2.01 (Allrod Rochow)
• Heat of Fusion: 50.2kJ/mol
• Incompatibilities:

• Ionization Potential
  • First: 8.298
  • Second: 25.154
  • Third: 37.93
• Valence Electron Potential (-eV): 190

Physical Properties of Boron

• Atomic Mass Average: 10.811
• Boiling Point: 4275K 4002°C 7236°F
• Coefficient of lineal thermal expansion/K^-1: 5E^-6
• Conductivity

  Electrical: 1.0E^-12 10⁶/cm
  Thermal: 0.274 W/cmK

• Density: 2.34g/cc @ 300K
• Description:

  Yellow-brown non-metallic crystal.

• Elastic Modulus:
  • Bulk: 320/GPa
• Enthalpy of Atomization: 573.2 kJ/mole @ 25°C
• Enthalpy of Fusion: 22.18 kJ/mole
• Enthalpy of Vaporization: 480 kJ/mole
• Flammablity Class:
• Freezing Point: see melting point
• Hardness Scale
  • Mohs: 9.3
  • Vickers: 49000 MN m^-2
• Heat of Vaporization: 489.7kJ/mol
• Melting Point: 2573K 2300°C 4172°F
  
• Molar Volume: 4.68 cm³/mole
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 1.02J/gK
• Vapor Pressure = 0.348Pa@2300°C

Regulatory / Health

• CAS Number
  • 7440-42-8
• OSHA Permissible Exposure Limit (PEL)
  • No limits set by OSHA
• OSHA PEL Vacated 1989
  • No limits set by OSHA
• NIOSH Recommended Exposure Limit (REL)
  • No limits set by NIOSH
• Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  • Blood/mg dm^-3: 0.13
  • Bone/p.p.m: 1.1-3.3
  • Liver/p.p.m: 0.4-3.3
  • Muscle/p.p.m: 0.33-1
  • Daily Dietary Intake: 1-3 mg
  • Total Mass In Avg. 70kg human: 18 mg
• Discovery Year: 1808
• Name Origin:

  From borax and carbon.

• Abundance of Boron:
  • Earth's Crust/p.p.m.: 950
  • Seawater/p.p.m.: 4.41
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 2.63
• Sources of Boron:

  Obtained from kernite, a kind of borax (Na₂B₄O₇·10H₂O). Annual world wide production around 1,000,000 tons per year (B₂O₃). Main mining areas are USA, Tibet, Chile, Turkey

• Uses of Boron:

  Used with titanium and tungsten to make light weight heat resistant alloys. Also tennis rackets, regulators in nuclear plants, heat resistant glass and eye disinfectant.

• Additional Notes:

  Boron is never found in the elemental form in nature. It was first obtained by Moissan in 1895 by reduction of boric anhydride (B₂O₃) with magnesium in a thermite-type reaction (Moissan, Ann. Chim Phys 7:6, 296, 1895). This is still used for obtaining large quantities of impure boron. Highly purified crystalline boron is obtained by vapor phase reduction of the compound boron trichloride with hydrogen on electrically heated filaments in a flow system (Stern, Lynds, Journal of Electrochemical Society, 105, 676. 1958).

[Last update: 2/22/2007]

Boron Menu

• Boron Page One
  • Overview of Boron
  • Boron's Name in Other Languages
  • Atomic Structure of Boron
  • Chemical Properties of Boron
  • Physical Properties of Boron
  • Regulatory / Health
  • Who/When/Where/How
• Boron Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Boron Page Three
  • Common Chemical Compounds of Boron

Related Resources

• Anatomy of the Atom
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• Molarity, Molality and Normality
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• Molar Mass Calculations and Javascript Calculator
  Molar mass calculations are explained and there is a JavaScript calculator to aid calculations.
• Chemical Database
  This database focuses on the most common chemical compounds used in the home and industry.

Citing this page

If you need to cite this page, you can copy this text:

Kenneth Barbalace. Periodic Table of Elements - Boron – B. EnvironmentalChemistry.com. 1995 - 2009. Accessed on-line: 7/4/2009
http://EnvironmentalChemistry.com/yogi/periodic/B.html
.