Pm
Promethium
PROMETHIUM
TRANSITION ELEMENT: LANTHANIDE
| Atomic number: | 61 |
| Group numbers: | 3 |
| Period: | 6 |
| Electronic configuration: | [Xe] 4f5 6s2 |
| Formal oxidation number: | +3 |
| Electronegativities: | - |
| Atomic radius / pm: | 183.4 |
| Relative atomic mass: | - |
Promethium was discovered by Jacob Akiba Marinsky, Lawrence Elgin Glendenin, and Charles DuBois Coryell (US) in 1947. Named after Prometheus in Greek mythology, who stole fire from the gods. It is a rare earth metal of synthetic origin on the earth, naturally made in stars. It is Poisonous, radiotoxic and radioactive. Promethium does not occur naturally. It is found among fission products of uranium, thorium and plutonium. It has been used as a source of radioactivity for thickness-measuring gages.
| Density / g dm-3: | 7220 | (298 K) |
| Molar volume / cm3mol-1: | 20.08 | (298 K) |
| Electrical resistivity / µΩcm: | - | (20 °C) |
| Thermal conductivity / W m-1K-1: | 17.9 |
| Melting point / °C: | 1042 |
| Boiling point / °C: | 3000 |
| Heat of fusion / kJ mol-1: | 12.6 |
| Heat of vaporization / kJ mol-1: | - |
| Heat of atomization / kJ mol-1: | 308 |
| First ionization energy / kJ mol-1: | 538.39 |
| Second ionization energy / kJ mol-1: | 1051.70 |
| Third ionization energy / kJ mol-1: | 2151.64 |
| in the atmosphere / ppm: | - |
| in the Earth's crust / ppm: | - |
| in the oceans / ppm: | - |
| Crystal structure: | hexagonal |
| Unit-cell dimensions / pm: | - |
| Space group: | - |
| Isotope | Relative atomic mass | Mass percent (%) |
|---|---|---|
| 145Pm | 144.912 76(2) | * |
| 146Pm | 145.914 70(3) | * |
| 147Pm | 146.915 15(2) | * |
| Balanced half-reaction | Eo / V | |
|---|---|---|
| 60 Neodymium | ← | 61 Promethium | → | 62 Samarium |
Citing this page:
Generalic, Eni. "Promethium." EniG. Periodic Table of the Elements. KTF-Split, 18 Jan. 2024. Web. {Date of access}. <https://www.periodni.com/pm.html>.
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