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Thorium

Metal radioactivesolid
Symbol: Th
Atomic number: 90
Atomic mass: 232.0381
Group: Actinide
CAS-number: 7440-29-1

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Physical data
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Physical data

Electronic dataThermal dataSteric data
Shells: 2, 8, 18, 32, 18, 10, 2
Orbitals: [Rn] 6d2 7s2
Electronegativity: --, 1.1
1. Ionization potential: 6.08 eV
2. Ionization potential: 11.504 eV
3. Ionization potential: 20.003 eV
Oxidation states: 4
Electrical conductivity: 0.0653 10^6
Melting point: 1750 °C
Boiling point: 4000 °C
Specific heat: 0.12 J/gK
Heat of fusion: 16.10 kJ/mol
Heat of vaporization: 514.40 kJ/mol
Thermal conductivity: 0.540 W/cmK
Atomic radius: -- Å
Ionic radius: 1.05 Å (+4)
Covalent radius: 1.65 Å
Atomic volume: 19.9 cm³/mol
Density (293 K): 11.7 g/cm³
Crystal structure: cubic face centered
cubic face centered

Isotopes

NuclideAbundance [%]MassSpinHalflifeDecay modeDecay tree
226Th 0 226.025 0 30.6m α View
227Th 0 227.028 3/2 18.72d α View
228Th 0 228.029 0 1.913y α View
229Th 0 229.032 5/2 7.34E03y α View
230Th 0 230.033 0 7.54E04y α View
231Th 0 231 5/2 1.063d β- View
232Th 100 232.038 0 1.40E10y α View
233Th 0 233 1/2 22.3m β- View
234Th 0 234 0 24.1d β- View

Other info

Name origin:Named for Thor, Norse god of thunder.
Description:Heavy, gray, soft, malleable, ductile, radioactive metal.
Discovered by:Jöns Berzelius
Year:1828
Place:Sweden
Sources:Found in various minerals like monazite and thorite.
Use(s):Used in making strong alloys. Also in ultraviolet photoelectric cells. It is a common ingredient in high-quality lenses. Bombarded with neutrons make uranium-233, a nuclear fuel.