- Isotopes of curium
-
Actinides Half-life Fission products 244Cm 241Pu f 250Cf 243Cmf 10–30 y 137Cs 90Sr 85Kr 232U f 238Pu f is for
fissile69–90 y 151Sm nc➔ 4n 249Cf f 242Amf 141–351 No fission product
has half-life 102
to 2×105 years241Am 251Cf f 431–898 240Pu 229Th 246Cm 243Am 5–7 ky 4n 245Cmf 250Cm 239Pu f 8–24 ky 233U f 230Th 231Pa 32–160 4n+1 234U 4n+3 211–290 99Tc 126Sn 79Se 248Cm 242Pu 340–373 Long-lived fission products 237Np 4n+2 1–2 My 93Zr 135Cs nc➔ 236U 4n+1 247Cmf 6–23 My 107Pd 129I 244Pu 80 My >7% >5% >1% >.1% 232Th 238U 235U f 0.7–12 Ty fission product yield Curium (Cm) is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope synthesized was 242Cm in 1944.
There are 21 known radioisotopes with atomic masses ranging from 232Cm to 252Cm. There are also four known nuclear isomers (243mCm, 244mCm, 245mCm, and 249mCm). The longest-lived isotope is 247Cm, with a half-life of 15.6 million years. The longest-lived isomer is 244mCm with a half-life of 34 milliseconds.
Table
nuclide
symbolZ
(p)N
(n)isotopic mass
(u)half-life decay
mode(s)[1][n 1]daughter
isotopes[n 2]spin excitation energy 232Cm 96 136 1? min 0+ 233Cm 96 137 233.05077(8) 1# min β+ 233Am 3/2+# α 229Pu 234Cm 96 138 234.05016(2) 51(12) s β+ 234Am 0+ α 230Pu 235Cm 96 139 235.05143(22)# 5# min β+ 235Am 5/2+# α 231Pu 236Cm 96 140 236.05141(22)# 10# min β+ 236Am 0+ α 232Pu 237Cm 96 141 237.05290(22)# 20# min β+ 237Am 5/2+# α 233Pu 238Cm 96 142 238.05303(4) 2.4(1) h EC (90%) 238Am 0+ α (10%) 234Pu 239Cm 96 143 239.05496(11)# ~2.9 h β+ (99.9%) 239Am (7/2-) α (.1%) 235Pu 240Cm 96 144 240.0555295(25) 27(1) d α (99.5%) 236Pu 0+ EC (.5%) 240Am SF (3.9×10−6%) (various) 241Cm 96 145 241.0576530(23) 32.8(2) d EC (99%) 241Am 1/2+ α (1%) 237Pu 242Cm[n 3] 96 146 242.0588358(20) 162.8(2) d α 238Pu 0+ SF (6.33×10−6%) (various) CD (10−14%)[n 4] 208Pb
34Siβ+β+ (rare) 242Pu 243Cm 96 147 243.0613891(22) 29.1(1) a α (99.71%) 239Pu 5/2+ EC (.29%) 243Am SF (5.3×10−9%) (various) 243mCm 87.4(1) keV 1.08(3) µs 1/2+ 244Cm[n 3] 96 148 244.0627526(20) 18.10(2) a α 240Pu 0+ SF (1.34×10−4%) (various) 244mCm 1040.188(12) keV 34(2) ms IT 244Cm 6+ 245Cm 96 149 245.0654912(22) 8.5(1)×103 a α 241Pu 7/2+ SF (6.1×10−7%) (various) 245mCm 355.90(10) keV 290(20) ns 1/2+ 246Cm 96 150 246.0672237(22) 4.76(4)×103 a α (99.97%) 242Pu 0+ SF (.0261%) (various) 247Cm 96 151 247.070354(5) 1.56(5)×107 a α 243Pu 9/2- 248Cm 96 152 248.072349(5) 3.48(6)×105 a α (91.74%) 244Pu 0+ SF (8.26%) (various) β-β- (rare) 248Cf 249Cm 96 153 249.075953(5) 64.15(3) min β- 249Bk 1/2(+) 249mCm 48.758(17) keV 23 µs (7/2+) 250Cm 96 154 250.078357(12) 8,300# a SF (80%)[n 5] (various) 0+ α (11%) 246Pu β- (9%) 250Bk 251Cm 96 155 251.082285(24) 16.8(2) min β- 251Bk (1/2+) 252Cm 96 156 252.08487(32)# <1 d β- 252Bk 0+ - ^ Abbreviations:
CD: Cluster decay
EC: Electron capture
IT: Isomeric transition
SF: Spontaneous fission - ^ Bold for stable isotopes
- ^ a b Most common isotopes
- ^ Heaviest known nuclide to undergo cluster decay
- ^ Lightest nuclide to undergo spontaneous fission as the main decay mode
Notes
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.
References
- Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode 2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. http://www.iupac.org/publications/pac/75/6/0683/pdf/.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. http://iupac.org/publications/pac/78/11/2051/pdf/. Lay summary.
- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode 2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0849304859.
Isotopes of americium Isotopes of curium Isotopes of berkelium Index to isotope pages · Table of nuclides Categories:- Curium
- Isotopes of curium
- Lists of isotopes by element
- ^ Abbreviations:
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