مراجع
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- ^ Plus radium (element 88). While actually a sub-actinide, it immediately precedes actinium (89) and follows a three-element gap of instability after بولونيوم (84) where no nuclides have half-lives of at least four years (the longest-lived nuclide in the gap is radon-222 with a half life of less than four days). Radium's longest lived isotope, at 1,600 years, thus merits the element's inclusion here.
- ^ Specifically from حرارة النيوترون fission of U-235, e.g. in a typical مفاعل نووي.
- ^ Milsted، J.؛ Friedman، A. M.؛ Stevens، C. M. (1965). "The alpha half-life of berkelium-247; a new long-lived isomer of berkelium-248". Nuclear Physics. ج. 71 ع. 2: 299. Bibcode:1965NucPh..71..299M. DOI:10.1016/0029-5582(65)90719-4.
"The isotopic analyses disclosed a species of mass 248 in constant abundance in three samples analysed over a period of about 10 months. This was ascribed to an isomer of Bk248 with a half-life greater than 9 y. No growth of Cf248 was detected, and a lower limit for the β− half-life can be set at about 104 y. No alpha activity attributable to the new isomer has been detected; the alpha half-life is probably greater than 300 y."
- ^ This is the heaviest nuclide with a half-life of at least four years before the "جزيرة الثبات".
- ^ Excluding those "نويدة ابتدائية" nuclides with half-lives significantly in excess of 232Th; e.g., while 113mCd has a half-life of only fourteen years, that of 113Cd is nearly eight quadrillion years.