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Promethium - Pm General Information Discovery The existence of promethium was predicted by Branner in 1902. In 1945 the element was first produced by the irradiation of neodymium by J.A. Marinsky, L.E. Glendenin and C.D. Coryell in Oak Ridge, USA. Appearance Promethium is a radioactive metal. Its salts luminesce in the dark with a pale greenish glow. Source Promethium is not found on the planet Earth. It has been identified on Andromeda. It can be produced by the irradiation of neodymium and praseodymium with neutrons, deuterons and alpha particles. It can also be prepared by ion exchange of atomic reactor fuel processing wastes. Uses Promethium is used as a nuclear-powered battery as it can capture light in photocells and convert it into an electric current. Such batteries are used in watches, radios and guided-missile instruments. They are no larger than a drawing pin. Biological Role Promethium has no known biological role, but is toxic due to its radioactivity. General Information Little is known about the properties of promethium. |
| Physical Information | |||
| Atomic Number | 61 | ||
| Relative Atomic Mass (12C=12.000) | 145 (radioactive) | ||
| Melting Point/K | 1441 | ||
| Boiling Point/K | ca 3000 | ||
| Density/kg m-3 | 7220 (298K) | ||
| Ground State Electron Configuration | [Xe]4f56s2 | ||
| Electron Affinity(M-M-)/kJ mol-1 | 50 |
| Key Isotopes | ||||||
| nuclide | 145Pm | 146Pm | 147Pm | 149Pm | 151Pm | |
| atomic mass | 144.9 | 146.9 | ||||
| natural abundance | 0% | 0% | 0% | 0% | 0% | |
| half-life | 17.7 yrs | 4.4 yrs | 2.62 yrs | 53.1 h | 28 h |
| Other Information | ||
| Enthalpy of Fusion/kJ mol-1 | 12.6 | |
| Enthalpy of Vaporisation/kJ mol-1 | n/a | |
| Oxidation States | ||
| PmIII | ||
| Covalent Bonds /kJ mol-1 | ||
| not applicable | ||
| Ionisation Energies/kJ mol-1 | ||
| M - M+ | 535.9 | |
| M+ - M2+ | 1052 | |
| M2+ - M3+ | 2150 | |
| M3+ - M4+ | 3970 | |
| M4+ - M5+ | ||
| M5+ - M6+ | ||
| M6+ - M7+ | ||
| M7+ - M8+ | ||
| M8+ - M9+ | ||
| M9+ - M10+ | ||
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