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单词 promethium
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promethium

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promethium in British English

or prometheum (prəˈmiːθɪəm)
noun
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.)
Word origin
C20: New Latin from Prometheus

promethium in American English

(proʊˈmiθiəm)
US
noun
a radioactive chemical element, one of the rare-earth elements, obtained from fissionof uranium or neutron bombardment of neodymium and used in phosphorescent paint, as a power source, X-ray source, etc.: symbol, Pm; at. no., 61
Word origin
ModL: so named (1949) for earlier prometheum, name proposed by G. M. Coryell for element isolated (1948) by J. A. Marinsky & L.E. Glendenin, U.S. physicists < Gr Promētheus (see UNRESOLVED CROSS REF) in reference to production by nuclear fission + -ium

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promethium

chemical
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更新时间：2024/11/13 16:44:32