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Periodic Table of Elements

Element Thorium – Th

Comprehensive data on the chemical element Thorium is provided on this page; including scores of properties, element names in many languages, most known nuclides of Thorium. 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.

Thorium Menu

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

Overview of Thorium

Thorium's Name in Other Languages

• Latin: Thorium
• Czech: Thorium
• Croatian: Torij
• French: Thorium
• German: Thorium - s
• Italian: Torio
• Norwegian: Thorium
• Portuguese: Tório
• Russian:
• Spanish: Tório
• Swedish: Torium

Atomic Structure of Thorium

• Atomic Radius:
• Atomic Volume: 19.9cm³/mol
• Covalent Radius: 1.65Å
• Cross Section (Thermal Neutron Capture) _a/barns: 7.37
• Crystal Structure: Cubic face centered

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶d¹⁰ 4s²p⁶d¹⁰f¹⁴ 5s²p⁶d¹⁰ 6s²p⁶d² 7s²

• Electrons per Energy Level: 2,8,18,32,18,10,2

  Shell Model
  

• Ionic Radius: 0.972Å
• Filling Orbital: 6d²
• Number of Electrons (with no charge): 90
• Number of Neutrons (most common/stable nuclide): 142
• Number of Protons: 90
• Oxidation States: 4
• Valence Electrons: 6d² 7s²

  Electron Dot Model
  

Chemical Properties of Thorium

• Electrochemical Equivalent: 2.1643g/amp-hr
• Electron Work Function: 3.41eV
• Electronegativity: 1.3 (Pauling); 1.11 (Allrod Rochow)
• Heat of Fusion: 16.1kJ/mol
• Incompatibilities:

• Ionization Potential
  • First: 6.08
  • Second: 11.504
  • Third: 20.003
• Valence Electron Potential (-eV): 59.3

Physical Properties of Thorium

• Atomic Mass Average: 232.0381
• Boiling Point: 5061K 4788°C 8650°F
• Coefficient of lineal thermal expansion/K^-1: 12.5E^-6
• Conductivity

  Electrical: 0.0653 10⁶/cm
  Thermal: 0.54 W/cmK

• Density: 11.724g/cc @ 300K
• Description:

  Soft silvery radioactive metal that is ductile and soft.

• Elastic Modulus:
  • Bulk: 54/GPa
  • Rigidity: 30.8/GPa
  • Youngs: 78.3/GPa
• Enthalpy of Atomization: 565 kJ/mole @ 25°C
• Enthalpy of Fusion: 15.65 kJ/mole
• Enthalpy of Vaporization: 543.9 kJ/mole
• Flammablity Class:
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 400 MN m^-2
  • Mohs: 3
  • Vickers: 350 MN m^-2
• Heat of Vaporization: 514.4kJ/mol
• Melting Point: 2028K 1755°C 3191°F
  
• Molar Volume: 19.8 cm³/mole
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.12J/gK

Regulatory / Health

• CAS Number
  • 7440-29-1
• NFPA 704
  • Health:
  • Fire:
  • Reactivity:
  • Special Hazard: Radioactive
  <
  • 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: 0.00016
    • Bone/p.p.m: 0.02-0.012
    • Liver/p.p.m: n/a
    • Muscle/p.p.m: n/a
    • Daily Dietary Intake: 0.00005-0.003 mg
    • Total Mass In Avg. 70kg human: 0.1 mg

  Who / Where / When / How

  • Discoverer: WJöns Berzelius
  • Discovery Location: Stockholm Sweden
  • Discovery Year: 1829
  • Name Origin:

    Named for Thor the Scandinavian god of war.

  • Abundance of Thorium:
    • Earth's Crust/p.p.m.: 12
    • Seawater/p.p.m.: 9.2
    • Atmosphere/p.p.m.: N/A
    • Sun (Relative to H=1E¹²): 2
  • Sources of Thorium:

    Found in various minerals like monazite and thorite and dispersed on pegmatite rocks. Annual world wide production is around 31,000 tons. Primary mining areas are USA, Brazil, India Sri Lanka, Madagascar, Russia and Australia.

  • Uses of Thorium:

    Used in making strong alloys. Also in ultraviolet photoelectric cells. Bombarded with neutrons make uranium-233, a nuclear fuel.

  • Additional Notes:

  [Last update: 2/22/2007]

  Notes below

  Thorium Menu

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

  Related Resources

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  • Chemical Database
    This database focuses on the most common chemical compounds used in the home and industry.

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