a radioactive chemical element, one of the rare-earth elements, obtained from fission of uranium or neutron bombardment of neodymium and used in phosphorescent paint, as a power source, X-ray source, etc.: symbol, Pm; at. no. 61
Origin of promethiumModL: so named (1949) for earlier prometheum, name proposed by G. M. Coryell, wife of one of the discoverers from Classical Greek Prom?theus (see Prometheus) in reference to production by nuclear fission + -ium
A radioactive element of the lanthanide series that is prepared by fission of uranium or by neutron bombardment of neodymium and has over 30 isotopes, the most stable of which have half-lives of 2.62 years (Pm-147), 5.53 years (Pm-146), and 17.7 years (Pm-145). Promethium-147, the most easily obtained isotope, is used as a source of beta rays. Atomic number 61; melting point 1,042°C; boiling point 3000°C; specific gravity 7.264 (25°C); valence 3. See Periodic Table.
Origin of promethiumFrom Prometheus
- A metallic chemical element (symbol Pm) with an atomic number of 61.