Thorium (pronounced /ˈθɔəriəm/, THOHR-ee-əm) is a chemical element with the symbol Th and atomic number 90. It is a naturally occurring, slightly radioactive metal. Thorium is estimated to be about three to four times more abundant than uranium in the Earth's crust. Thorium was successfully used as an alternative nuclear fuel to uranium in the molten-salt reactor experiment (MSR) from 1964 to 1969 to produce thermal energy, as well as in several ...
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Thorium
Chemical Element
The 90th Element in the Periodic Table
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Actinium
Actinium (pronounced /ækˈtɪniəm/, ak-TIN-nee-əm) is a radioactive chemical element with the symbol Ac and atomic number 89, which was discovered in...
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Protactinium
Protactinium (pronounced /ˌproʊtækˈtɪniəm/, PROH-tak-TIN-ee-əm) is a chemical element with the symbol Pa and atomic number 91. Its longest-lived and...
Symbol:
- Th
Atomic mass:
| Mass | Uncertainty |
|---|---|
|
|
Electronegativity (Pauling scale):
- 1.3
Van der Waals radius:
- 240 pm (0.00000945 )
Isotopes:
- Thorium-230
- Thorium-232
- Thorium-220
- Thorium-233
- Thorium-212
- Thorium-234
- Thorium-237
- Thorium-211
- Thorium-218
- Thorium-222
Melting Point:
- 1,754.85 °C (3190.76 °F )
Boiling Point:
- 4,786.85 °C (8648.42 °F )
Chemical series:
Periodic table block:
Ionization Energy:
- 6.3067 eV (0.0000063067 MeV )
Discovery Date:
- 1828
Electron Configuration:
- Rn 6d2 7s2