Isotopes of berkelium – Wikipedia

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Nuclides with atomic number of 97 but with different mass numbers

Berkelium (97Bk) is an artificial element, and thus a standard atomic weight cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope to be synthesized was 243Bk in 1949. There are 19 known radioisotopes, from 233Bk to 253Bk (with the exception of 235Bk and 237Bk), and 6 nuclear isomers. The longest-lived isotope is 247Bk with a half-life of 1,380 years.

List of isotopes[edit]

Nuclide
[n 1]		 Z N Isotopic mass (Da)
[n 2][n 3]		 Half-life Decay
mode
[n 4]		 Daughter
isotope		 Spin and
parity
[n 5][n 6]
Excitation energy[n 6]
233Bk[3] 97 136 21 s α 229Am
234Bk[4] 97 137 19(+6−4) s α (50%) 230Am
β+ (50%) 234Cm
236Bk 97 139 236.05733(43)# 22(+13−6) s[5] α 232Am
β+ 236Cm
238Bk 97 141 238.05828(31)# 2.40(8) min α 234Am
β+, SF (.048%) (various)
β+ (rare) 238Cm
239Bk[6] 97 142 239.05828(25)# 100# s β+ (>99%) 239Cm (7/2+)
α (<1%) 235Am
SF (<1%) (various)
240Bk 97 143 240.05976(16)# 4.8(8) min β+ (90%) 240Cm
α (10%) 236Am
β+, SF (.002%) (various)
241Bk 97 144 241.06023(22)# 4.6(4) min α 237Am (7/2+)
β+ (rare) 241Cm
242Bk 97 145 242.06198(22)# 7.0(13) min β+ (99.99%) 242Cm 2−#
β+, SF (3×10−4%) (various)
242mBk 200(200)# keV 600(100) ns SF (various)
243Bk 97 146 243.063008(5) 4.5(2) h β+ (99.85%) 243Cm (3/2−)
α (.15%) 239Am
244Bk 97 147 244.065181(16) 4.35(15) h β+ (99.99%) 244Cm (4−)#
α (.006%) 240Am
245Bk 97 148 245.0663616(25) 4.94(3) d EC (99.88%) 245Cm 3/2−
α (.12%) 241Am
246Bk 97 149 246.06867(6) 1.80(2) d EC (99.8%) 246Cm 2(−)
α (.2%) 242Am
247Bk 97 150 247.070307(6) 1.38(25)×103 y α 243Am (3/2−)
SF (rare) (various)
248Bk 97 151 248.07309(8)# >300 y[7] α 244Am 6+#
248mBk 30(70)# keV 23.7(2) h β− 248Cf 1(−)
249Bk[n 7] 97 152 249.0749867(28) 330(4) d β− 249Cf 7/2+
α (.00145%) 245Am
SF (4.7×10−8%) (various)
249mBk 8.80(10) keV 300 μs IT 249Bk (3/2−)
250Bk 97 153 250.078317(4) 3.212(5) h β− 250Cf 2−
250m1Bk 35.59(5) keV 29(1) μs IT 250Bk (4+)
250m2Bk 84.1(21) keV 213(8) μs (7+)
251Bk 97 154 251.080760(12) 55.6(11) min β− 251Cf (3/2−)#
α (10−5%) 247Am
251mBk 35.5(13) keV 58(4) μs IT 251Bk (7/2+)#
252Bk 97 155 252.08431(22)# 1.8(5) min β− 252Cf
α 248Am
253Bk 97 156 253.08688(39)# 10# min β− 253Cf
This table header & footer:
  1. ^ mBk – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^
    Modes of decay:
  5. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  6. ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  7. ^ Easiest isotope to synthesize

Actinides vs fission products[edit]

See also[edit]

References[edit]

  1. ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). “The NUBASE2020 evaluation of nuclear properties” (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ^ 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. 71 (2): 299. doi:10.1016/0029-5582(65)90719-4.
  3. ^ “Observation of new neutron-deficient isotopes with Z ≥ 92
    in multinucleon transfer reactions” http://inspirehep.net/record/1383747/files/scoap3-fulltext.pdf
  4. ^ Kaji, D.; Morimoto, K.; Haba, H.; Ideguchi, E.; Koura, H.; Morita, K. (2016). “Decay Properties of New Isotopes 234Bk and 230Am, and Even–Even Nuclides 234Cm and 230Pu” (PDF). Journal of the Physical Society of Japan. 84 (15002): 015002. doi:10.7566/JPSJ.85.015002.
  5. ^ Konki, J.; et al. (10 Jan 2017). “Towards saturation of the electron-capture delayed fission probability: The new isotopes 240Es and 236Bk”. Physics Letters B. 764: 265–270. Bibcode:2017PhLB..764..265K. doi:10.1016/j.physletb.2016.11.038. ISSN 0370-2693.
  6. ^ Antalic, S.; Heßberger, F. P.; Hofmann, S.; et al. (2010). “Studies of neutron-deficient mendelevium isotopes at SHIP”. European Physical Journal A. 43 (1): 35–44. doi:10.1140/epja/i2009-10896-0.
  7. ^ 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. 71 (2): 299. Bibcode:1965NucPh..71..299M. doi:10.1016/0029-5582(65)90719-4.
  8. ^ Plus radium (element 88). While actually a sub-actinide, it immediately precedes actinium (89) and follows a three-element gap of instability after polonium (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.
  9. ^ Specifically from thermal neutron fission of uranium-235, e.g. in a typical nuclear reactor.
  10. ^ 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. 71 (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 [years]. No growth of Cf248 was detected, and a lower limit for the β− half-life can be set at about 104 [years]. No alpha activity attributable to the new isomer has been detected; the alpha half-life is probably greater than 300 [years].”
  11. ^ This is the heaviest nuclide with a half-life of at least four years before the “sea of instability”.
  12. ^ Excluding those “classically stable” 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.



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