Isotopes of curium explained

Curium (Cm) is an artificial element with an atomic number of 96. Because it is an artificial element, a standard atomic weight cannot be given, and it has no stable isotopes. The first isotope synthesized was Cm in 1944, which has 146 neutrons.

There are 19 known radioisotopes ranging from Cm to Cm. There are also ten known nuclear isomers. The longest-lived isotope is Cm, with half-life 15.6 million years – orders of magnitude longer than that of any known isotope beyond curium, and long enough to study as a possible extinct radionuclide that would be produced by the r-process.[1] [2] The longest-lived known isomer is Cm with a half-life of 1.12 seconds.

List of isotopes

|-id=Curium-233| rowspan=2|Cm| rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 137| rowspan=2|233.05077(8)| rowspan=2|| β (80%)| Am| rowspan=2|3/2+#|-| α (20%)| Pu|-id=Curium-234| rowspan=3|Cm| rowspan=3 style="text-align:right" | 96| rowspan=3 style="text-align:right" | 138| rowspan=3|234.05016(2)| rowspan=3|52(9) s| β (71%)| Am| rowspan=3|0+|-| α (27%)| Pu|-| SF (2%)| (various)|-id=Curium-235| rowspan=2|Cm[3] | rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 139| rowspan=2|235.05143(22)#| rowspan=2|| β (99.0%)| Am| rowspan=2|(5/2+)|-| α (1.0%)| Pu|-id=Curium-236| rowspan=3|Cm| rowspan=3 style="text-align:right" | 96| rowspan=3 style="text-align:right" | 140| rowspan=3|236.05141(22)#| rowspan=3|6.8(8) min| β (82%)| Am| rowspan=3|0+|-| α (18%)| Pu|-| SF (<0.1%)[4] | (various)|-id=Curium-237| rowspan=2|Cm[5] [3] | rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 141| rowspan=2|237.05290(22)#| rowspan=2|>660 s| β| Am| rowspan=2|(5/2+)|-| α (<1%)| Pu|-id=Curium-238| rowspan=2|Cm[5] | rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 142| rowspan=2|238.05303(4)| rowspan=2|2.2(4) h| EC (~94%)| Am| rowspan=2|0+|-| α (~6%)| Pu|-id=Curium-239| rowspan=2|Cm| rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 143| rowspan=2|239.05496(11)#| rowspan=2|2.5(4) h| β| Am| rowspan=2|(7/2−)|-| α (6.2x10%)| Pu|-id=Curium-240| rowspan=3|Cm| rowspan=3 style="text-align:right" | 96| rowspan=3 style="text-align:right" | 144| rowspan=3|240.0555295(25)| rowspan=3|27(1) d| α (99.5%)| Pu| rowspan=3|0+|-| EC (.5%)| Am|-| SF (3.9×10%)| (various)|-id=Curium-241| rowspan=2|Cm| rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 145| rowspan=2|241.0576530(23)| rowspan=2|32.8(2) d| EC (99%)| Am| rowspan=2|1/2+|-| α (1%)| Pu|-id=Curium-242| rowspan=3|Cm[6] | rowspan=3 style="text-align:right" | 96| rowspan=3 style="text-align:right" | 146| rowspan=3|242.0588358(20)| rowspan=3|162.8(2) d| α| Pu| rowspan=3|0+|-| SF (6.33×10%)| (various)|-| CD (10%)[7] | Pb
Si|-id=Curium-242m| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 2800(100) keV| 180(70) ns| | | |-id=Curium-243| rowspan=3|Cm| rowspan=3 style="text-align:right" | 96| rowspan=3 style="text-align:right" | 147| rowspan=3|243.0613891(22)| rowspan=3|29.1(1) y| α (99.71%)| Pu| rowspan=3|5/2+|-| EC (.29%)| Am|-| SF (5.3×10%)| (various)|-id=Curium-243m| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 87.4(1) keV| 1.08(3) μs| IT| Cm| 1/2+|-id=Curium-244| rowspan=2|Cm| rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 148| rowspan=2|244.0627526(20)| rowspan=2|18.10(2) y| α| Pu| rowspan=2|0+|-| SF (1.34×10%)| (various)|-id=Curium-244m1| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 1040.188(12) keV| 34(2) ms| IT| Cm| 6+|-id=Curium-244m2| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 1100(900)# keV| >500 ns| SF| (various)| |-id=Curium-245| rowspan=2|Cm| rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 149| rowspan=2|245.0654912(22)| rowspan=2|8.5(1)×10 y| α| Pu| rowspan=2|7/2+|-| SF (6.1×10%)| (various)|-id=Curium-245m| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 355.92(10) keV| 290(20) ns| IT| Cm| 1/2+|-id=Curium-246| rowspan=2|Cm| rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 150| rowspan=2|246.0672237(22)| rowspan=2|4.76(4)×10 y| α (99.97%)| Pu| rowspan=2|0+|-| SF (.0261%)| (various)|-id=Curium-246m| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 1179.66(13) keV| 1.12(0.24) s| IT| Cm| 8−|-id=Curium-247| Cm| style="text-align:right" | 96| style="text-align:right" | 151| 247.070354(5)| 1.56(5)×10 y| α| Pu| 9/2−|-id=Curium-247m1| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 227.38(19) keV| 26.3(0.3) μs| IT| Cm| 5/2+|-id=Curium-247m2| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 404.90(3) keV| 100.6(0.6) ns| IT| Cm| 1/2+|-id=Curium-248| rowspan=2|Cm| rowspan=2 style="text-align:right" | 96| rowspan=2 style="text-align:right" | 152| rowspan=2|248.072349(5)| rowspan=2|3.48(6)×10 y| α (91.74%)| Pu| rowspan=2|0+|-| SF (8.26%)| (various)|-id=Curium-248m| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 1458.1(1) keV| 146(18) μs| IT| Cm| (8−)|-id=Curium-249| Cm| style="text-align:right" | 96| style="text-align:right" | 153| 249.075953(5)| 64.15(3) min| β| Bk| 1/2(+)|-id=Curium-249m| style="text-indent:1em" | Cm| colspan="3" style="text-indent:2em" | 48.758(17) keV| 23 μs| α| Pu| (7/2+)|-id=Curium-250| rowspan=3|Cm| rowspan=3 style="text-align:right" | 96| rowspan=3 style="text-align:right" | 154| rowspan=3|250.078357(12)| rowspan=3|8300# y| SF (74%)[8] | (various)| rowspan=3|0+|-| α (18%)| Pu|-| β (8%)| Bk|-id=Curium-251| Cm| style="text-align:right" | 96| style="text-align:right" | 155| 251.082285(24)| 16.8(2) min| β| Bk| (1/2+)

Actinides vs fission products

References

Notes and References

  1. Côté . Benoit . Eichler . Marius . Yagüe López . Andrés . Vassh . Nicole . Mumpower . Matthew R. . Világos . Blanka . Soós . Benjámin . Arcones . Almudena. Almudena Arcones . Sprouse . Trevor M. . Surman . Rebecca . Pignatari . Marco . Pető . Mária K. . Wehmeyer . Benjamin . Rauscher . Thomas . Lugaro . Maria . 129I and 247Cm in meteorites constrain the last astrophysical source of solar r-process elements . Science . 26 February 2021 . 371 . 6532 . 945–948 . 10.1126/science.aba1111. 33632846 . 2006.04833 . 2021Sci...371..945C . 232050526 .
  2. Davis . A.M. . McKeegan . K.D. . Short-Lived Radionuclides and Early Solar System Chronology . Treatise on Geochemistry . 2014 . 383 . 10.1016/B978-0-08-095975-7.00113-3. 9780080983004 .
  3. Khuyagbaatar . J. . Heßberger . F. P. . Hofmann . S. . Ackermann . D. . Burkhard . H. G. . Heinz . S. . Kindler . B. . Kojouharov . I. . Lommel . B. . Mann . R. . Maurer . J. . Nishio . K. . α decay of Fm 243 143 and Fm 245 145, and of their daughter nuclei . Physical Review C . 12 October 2020 . 102 . 4 . 044312 . 10.1103/PhysRevC.102.044312 . 241259726 . 24 June 2023 . en . 2469-9985.
  4. Khuyagbaatar . J. . Heßberger . F. P. . Hofmann . S. . Ackermann . D. . Comas . V. S. . Heinz . S. . Heredia . J. A. . Kindler . B. . Kojouharov . I. . Lommel . B. . Mann . R. . Nishio . K. . Yakushev . A. . The new isotope 236Cm and new data on 233Cm and 237, 238, 240Cf . The European Physical Journal A . 1 October 2010 . 46 . 1 . 59–67 . 10.1140/epja/i2010-11026-9 . 2010EPJA...46...59K . 122809010 . 24 June 2023 . en . 1434-601X.
  5. Asai . M. . Tsukada . K. . Ichikawa . S. . Sakama . M. . Haba . H. . Nishinaka . I. . Nagame . Y. . Goto . S. . Kojima . Y. . Oura . Y. . Shibata . M. . α decay of 238Cm and the new isotope 237Cm . Physical Review C . 20 June 2006 . 73 . 6 . 067301 . 10.1103/PhysRevC.73.067301 . 24 June 2023.
  6. Most common isotopes
  7. Heaviest known nuclide to undergo cluster decay
  8. The nuclide with the lowest atomic number known to undergo spontaneous fission as the main decay mode

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