Isotopes of curium

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Template:Short description Template:Infobox curium isotopes Curium (96Cm) 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 242Cm in 1944, which has 146 neutrons.

There are 19 known radioisotopes ranging from 233Cm to 251Cm. There are also ten known nuclear isomers. The longest-lived isotope is 247Cm, 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] It is followed by 248Cm, which has a half-life of 348,000 years. The longest-lived known isomer is 246mCm with a half-life of 1.12 seconds.

List of isotopes


Template:Isotopes table |-id=Curium-233 | rowspan=2|233Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 137 | rowspan=2|233.05077(9) | rowspan=2 style="text-align:center" | 2010 | rowspan=2|27(10) s | β+ (80%) | 233Am | rowspan=2|3/2+# |- | α (20%) | 229Pu |-id=Curium-234 | rowspan=3|234Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 138 | rowspan=3|234.050159(18) | rowspan=3 style="text-align:center" | 2016 | rowspan=3|52(9) s | β+ (71%) | 234Am | rowspan=3|0+ |- | α (27%) | 230Pu |- | SF (2%) | (various) |-id=Curium-235 | rowspan=2|235Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 139 | rowspan=2|235.05155(11)# | rowspan=2 style="text-align:center" | 2020 | rowspan=2|7(3) min | β+? (96%) | 235Am | rowspan=2|5/2+# |- | α (4%) | 231Pu |-id=Curium-236 | rowspan=2|236Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 140 | rowspan=2|236.051372(19) | rowspan=2 style="text-align:center" | 2010 | rowspan=2|6.8(8) min | β+ (82%) | 236Am | rowspan=2|0+ |- | α (18%) | 232Pu |-id=Curium-237 | 237Cm | style="text-align:right" | 96 | style="text-align:right" | 141 | 237.05287(8) | style="text-align:center" | 2002 | >10# min | α (?%) | 233Pu | 5/2+# |-id=Curium-238 | rowspan=3|238Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 142 | rowspan=3|238.053082(13) | rowspan=3 style="text-align:center" | 1994 | rowspan=3|2.2(4) h | EC? (96.11%) | 238Am | rowspan=3|0+ |- | α (3.84%) | 234Pu |- | SF (0.048%) | (various) |-id=Curium-239 | rowspan=2|239Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 143 | rowspan=2|239.05491(16) | rowspan=2 style="text-align:center" | 2008 | rowspan=2|2.5(4) h | β+ | 239Am | rowspan=2|7/2−# |- | α (6.2x10−3%) | 235Pu |-id=Curium-240 | rowspan=2|240Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 144 | rowspan=2|240.0555282(20) | rowspan=2 style="text-align:center" | 1949 | rowspan=2|30.4(37) d | α | 236Pu | rowspan=2|0+ |- | SF (3.9×10−6%) | (various) |-id=Curium-241 | rowspan=2|241Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 145 | rowspan=2|241.0576512(17) | rowspan=2 style="text-align:center" | 1952 | rowspan=2|32.8(2) d | EC (99.0%) | 241Am | rowspan=2|1/2+ |- | α (1.0%) | 237Pu |-id=Curium-242 | rowspan=3|242Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 146 | rowspan=3|242.0588342(12) | rowspan=3 style="text-align:center" | 1949 | rowspan=3|162.8(2) d | α[n 1] | 238Pu | rowspan=3|0+ |- | SF (6.2×10−6%) | (various) |- | CD (1.1×10−14%)[n 2] | 208Pb
34Si |-id=Curium-242m | rowspan=2 style="text-indent:1em" | 242mCm | rowspan=2 colspan="3" style="text-indent:2em" | 2800(100) keV | rowspan=2 style="text-align:center" | 1971 | rowspan=2 | 180(70) ns | SF? | (various) | rowspan=2 | |- | IT? | 242Cm |-id=Curium-243 | rowspan=3|243Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 147 | rowspan=3|243.0613873(16) | rowspan=3 style="text-align:center" | 1950 | rowspan=3|29.1(1) y | α (99.71%) | 239Pu | rowspan=3|5/2+ |- | EC (0.29%) | 243Am |- | SF (5.3×10−9%) | (various) |-id=Curium-243m | style="text-indent:1em" | 243mCm | colspan="3" style="text-indent:2em" | 87.4(1) keV | style="text-align:center" | 1975 | 1.08(3) μs | IT | 243Cm | 1/2+ |-id=Curium-244 | rowspan=2|244Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 148 | rowspan=2|244.0627506(12) | rowspan=2 style="text-align:center" | 1950 | rowspan=2|18.11(3) y | α | 240Pu | rowspan=2|0+ |- | SF (1.37×10−4%) | (various) |-id=Curium-244m1 | style="text-indent:1em" | 244m1Cm | colspan="3" style="text-indent:2em" | 1040.181(11) keV | style="text-align:center" | 1963 | 34(2) ms | IT | 244Cm | 6+ |-id=Curium-244m2 | style="text-indent:1em" | 244m2Cm | colspan="3" style="text-indent:2em" | 1100(900)# xkeV | style="text-align:center" | (1969)[n 3] | >500 ns | SF | (various) | |-id=Curium-245 | rowspan=2|245Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 149 | rowspan=2|245.0654910(12) | rowspan=2 style="text-align:center" | 1954 | rowspan=2|8250(70) y | α | 241Pu | rowspan=2|7/2+ |- | SF (6.1×10−7%) | (various) |-id=Curium-245m | style="text-indent:1em" | 245mCm | colspan="3" style="text-indent:2em" | 355.92(10) keV | style="text-align:center" | 1975 | 290(20) ns | IT | 245Cm | 1/2+ |-id=Curium-246 | rowspan=2|246Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 150 | rowspan=2|246.0672220(16) | rowspan=2 style="text-align:center" | 1954 | rowspan=2|4706(40) y | α (99.97%) | 242Pu | rowspan=2|0+ |- | SF (0.02615%) | (various) |-id=Curium-246m | style="text-indent:1em" | 246mCm | colspan="3" style="text-indent:2em" | 1179.66(13) keV | style="text-align:center" | 2008 | 1.12(24) s | IT | 246Cm | 8− |-id=Curium-247 | 247Cm | style="text-align:right" | 96 | style="text-align:right" | 151 | 247.070353(4) | style="text-align:center" | 1954 | 1.56(5)×107 y | α[n 4] | 243Pu | 9/2− |-id=Curium-247m1 | style="text-indent:1em" | 247m1Cm | colspan="3" style="text-indent:2em" | 227.38(19) keV | style="text-align:center" | 1968 | 26.3(3) μs | IT | 247Cm | 5/2+ |-id=Curium-247m2 | style="text-indent:1em" | 247m2Cm | colspan="3" style="text-indent:2em" | 404.90(3) keV | style="text-align:center" | 2003 | 100.6(6) ns | IT | 247Cm | 1/2+ |-id=Curium-248 | rowspan=2|248Cm | rowspan=2 style="text-align:right" | 96 | rowspan=2 style="text-align:right" | 152 | rowspan=2|248.0723491(25) | rowspan=2 style="text-align:center" | 1956 | rowspan=2|3.48(6)×105 y | α (91.61%)[n 5] | 244Pu | rowspan=2|0+ |- | SF (8.39%) | (various) |-id=Curium-248m | style="text-indent:1em" | 248mCm | colspan="3" style="text-indent:2em" | 1458.1(10) keV | style="text-align:center" | 2019 | 146(18) μs | IT | 248Cm | 8−# |-id=Curium-249 | 249Cm | style="text-align:right" | 96 | style="text-align:right" | 153 | 249.0759540(25) | style="text-align:center" | 1956 | 64.15(3) min | β− | 249Bk | 1/2+ |-id=Curium-249m | style="text-indent:1em" | 249mCm | colspan="3" style="text-indent:2em" | 48.76(4) keV | style="text-align:center" | (1966)[n 6] | 23 μs | | | 7/2+ |-id=Curium-250 | rowspan=3|250Cm | rowspan=3 style="text-align:right" | 96 | rowspan=3 style="text-align:right" | 154 | rowspan=3|250.078358(11) | rowspan=3 style="text-align:center" | 1966 | rowspan=3|8300# y[n 7] | SF[n 8] | (various) | rowspan=3|0+ |- | α (?%) | 246Pu |- | β− (?%) | 250Bk |-id=Curium-251 | 251Cm | style="text-align:right" | 96 | style="text-align:right" | 155 | 251.082285(24) | style="text-align:center" | 1978 | 16.8(2) min | β− | 251Bk | (3/2+) Template:Isotopes table/footer

Actinides vs fission products

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Actinides and fission products by half-life Lua error in package.lua at line 80: module 'Module:Navbar/configuration' not found.
Actinides[4] by decay chain Half-life
range (a) 		Fission products of 235U by yield[5]
4n
(Thorium) 		4n + 1
(Neptunium) 		4n + 2
(Radium) 		4n + 3
(Actinium) 		4.5–7% 0.04–1.25% <0.001%
228Ra№ 4–6 a 155Euþ
248Bk[6] > 9 a
244Cmƒ 241Puƒ 250Cf 227Ac№ 10–29 a 90Sr 85Kr 113mCdþ
232Uƒ 238Puƒ 243Cmƒ 29–97 a 137Cs 151Smþ 121mSn
249Cfƒ 242mAmƒ 141–351 a

No fission products have a half-life
in the range of 100 a–210 ka ...

241Amƒ 251Cfƒ[7] 430–900 a
226Ra№ 247Bk 1.3–1.6 ka
240Pu 229Th 246Cmƒ 243Amƒ 4.7–7.4 ka
245Cmƒ 250Cm 8.3–8.5 ka
239Puƒ 24.1 ka
230Th№ 231Pa№ 32–76 ka
236Npƒ 233Uƒ 234U№ 150–250 ka 99Tc₡ 126Sn
248Cm 242Pu 327–375 ka 79Se₡
1.33 Ma 135Cs₡
237Npƒ 1.61–6.5 Ma 93Zr 107Pd
236U 247Cmƒ 15–24 Ma 129I₡
244Pu 80 Ma

... nor beyond 15.7 Ma[8]

232Th№ 238U№ 235Uƒ№ 0.7–14.1 Ga
Template:Ubli

References

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  1. ^ Page Module:Citation/CS1/styles.css has no content.Côté, Benoit; Eichler, Marius; Yagüe López, Andrés; Vassh, Nicole; Mumpower, Matthew R.; Világos, Blanka; Soós, Benjámin; Arcones, Almudena; Sprouse, Trevor M.; Surman, Rebecca; Pignatari, Marco; Pető, Mária K.; Wehmeyer, Benjamin; Rauscher, Thomas; Lugaro, Maria (26 February 2021). "129I and 247Cm in meteorites constrain the last astrophysical source of solar r-process elements". Science. 371 (6532): 945–948. arXiv:2006.04833. Bibcode:2021Sci...371..945C. doi:10.1126/science.aba1111. PMID 33632846. S2CID 232050526.
  2. ^ Page Module:Citation/CS1/styles.css has no content.Davis, A.M.; McKeegan, K.D. (2014). "Short-Lived Radionuclides and Early Solar System Chronology". Treatise on Geochemistry: 383. doi:10.1016/B978-0-08-095975-7.00113-3. ISBN 9780080983004.
  3. ^ Page Module:Citation/CS1/styles.css has no content."Adopted Levels for 250Cm" (PDF). NNDC Chart of Nuclides.
  4. ^ 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.
  5. ^ Specifically from thermal neutron fission of uranium-235, e.g. in a typical nuclear reactor.
  6. ^ Page Module:Citation/CS1/styles.css has no content.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]."
  7. ^ This is the heaviest nuclide with a half-life of at least four years before the "sea of instability".
  8. ^ 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 eight quadrillion years.
  • Isotope masses from:
    • Script error: No such module "Template wrapper".
  • Half-life, spin, and isomer data selected from the following sources.

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