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| Promethium | Prométhium | Prometij | Prometio | Promethium | ||||||||||||||||||||
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Pm Promethium |
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- Promethium was discovered by J. A. Marinsky, Lawrence Glendenin and Charles D. Coryell (USA) in 1945. Named after Prometheus in Greek mythology, who stole fire from the gods. It is rare earth metal of synthetic origin on the earth, naturally made in stars. Poison. Radiotoxic. Radioactive.
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TRANSITION ELEMENT: LANTHANIDE | |
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| Relative atomic mass: | [145] | Electronic configuration: | [Xe] 4f5 6s2 |
| Formal oxidation number: | +3 | Electronegativities: | - |
| Thermal conductivity: | 17.9 W m-1 K-1 | Electrical resistivity (20 °C): | - μΩcm |
| Atomic radius: | 183.4 pm | Standard state (20 °C): | solid |
| Density (g dm-3): | 7220 (298 K) | Molar volume (cm3 mol-1): | 20.08 (298 K) |
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THERMAL PROPERTIES | |
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| Melting point: | 1042 °C | Heat of fusion: | 12.6 kJ mol-1 |
| Boiling point: | 3000 °C | Heat of vaporization: | - kJ mol-1 |
| Critical temperature: | 6527 °C | Heat of atomization: | 308 kJ mol-1 |
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IONIZATION ENERGIES AND ABUNDANCE | |
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| 1st ionization energy: | 538.39 kJ mol-1 | Abundance of element (air): | - ppm |
| 2nd ionization energy: | 1051.70 kJ mol-1 | Abundance of element (Earth's crust): | - ppm |
| 3rd ionization energy: | 2151.64 kJ mol-1 | Abundance of element (oceans): | - ppm |
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ISOTOPES | |
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Isotopes | Relative atomic mass | Abundance (%) |
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143Pm | 142.910928(4) | * |
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145Pm | 144.912744(4) | * |
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147Pm | 146.915134(3) | * |
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MINERALS AND USES | |
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- Promethium does not occur naturally. Found among fission products of uranium, thorium and plutonium. It has been used as a source of radioactivity for thickness-measuring gages.
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REDUCTION POTENTIALS | |
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Balanced half-reaction | Eo / V | Annotation |
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