ALL meanings of promethium
pro·me·thi·um
P p - noun promethium a rare-earth, metallic, trivalent element. Symbol: Pm; atomic number: 61. 1
- noun promethium a radioactive element of the lanthanide series artificially produced by the fission of uranium. Symbol: Pm; atomic no: 61; half-life of most stable isotope, 145Pm: 17.7 years; valency: 3; melting pt: 1042°C; boiling pt: 2460°C (approx.) 0
- noun promethium 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 0