promethium  /prəm'iθiəm/

共發現 3 筆關於 [promethium] 的資料 (解釋內文之英文單字均可再點入查詢)

資料來源(1): pydict data [pydict]

  promethium
  烯土類元素

資料來源(2): WordNet (r) 2.0 [wn]

  promethium
       n : a soft silvery metallic element of the rare earth group
           having no stable isotope; was discovered in radioactive
           form as a fission product of uranium [syn: {Pm}, {atomic
           number 61}]

資料來源(3): Elements database 20001107 [elements]

  promethium
  Symbol: Pm
  Atomic number: 61
  Atomic weight: (147)
  Soft silvery metallic element, belongs to the lanthanoids. Pm-147, the
  only natural isotope, is radioactive and has a half-life of 252 years.
  Eighteen radioisotopes have been produced, but all have very short
  half-lives. Found only in nuclear decay waste. Pm-147 is of interest as a
  beta-decay source, however Pm-146 and Pm-148 have to be removed from it
  first, as they generate gamma radiation. Discovered by J.A. Marinsky,
  L.E. Glendenin and C.D. Coryell in 1947.