- Isotopes of europium
Naturally occurring
europium is composed of 2isotope s, 151Eu and 153Eu, with 153Eu being the most abundant (52.2%natural abundance ). While 153Eu is stable, 151Eu was recently found to be unstable toalpha decay withhalf-life of yr [Search for α decay of natural Europium, P. Belli, R. Bernabei, F. Cappell, R. Cerulli, C.J. Dai, F.A. Danevich, A. d'Angelo, A. Incicchitti, V.V. Kobychev, S.S. Nagorny, S. Nisi, F. Nozzoli, D. Prosperi, V.I. Tretyak, and S.S. Yurchenko, Nucl. Phys. A 789, 15 (2007) doi|10.1016/j.nuclphysa.2007.03.001] . Besides natural radioisotope 151Eu, 35 artificial radioisotopes have been characterized, with the most stable being 150Eu with ahalf-life of 36.9 years, 152Eu with a half-life of 13.516 years, and 154Eu with a half-life of 8.593 years. All of the remainingradioactive isotopes have half-lives that are less than 4.7612 years, and the majority of these have half-lives that are less than 12.2 seconds. This element also has 8meta state s, with the most stable being 150mEu (t½ 12.8 hours), 152m1Eu (t½ 9.3116 hours) and 152m2Eu (t½ 96 minutes).The primary
decay mode before the most abundant stable isotope, 153Eu, iselectron capture , and the primary mode after isbeta minus decay . The primarydecay product s before 153Eu are isotopes ofsamarium (Sm) and the primary products after are isotopes ofgadolinium (Gd).
Standard atomic mass: 151.964(1) u.Table
Notes
* Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
* 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 [http://www.nndc.bnl.gov/amdc/index.html Ame2003 Atomic Mass Evaluation] by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in "Nuclear Physics" A729 (2003).
* Isotopic compositions and standard atomic masses from [http://www.iupac.org/publications/pac/2003/7506/7506x0683.html Atomic weights of the elements. Review 2000 (IUPAC Technical Report)] . "Pure Appl. Chem." Vol. 75, No. 6, pp. 683-800, (2003) and [http://www.iupac.org/news/archives/2005/atomic-weights_revised05.html Atomic Weights Revised (2005)] .
* Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
** Audi, Bersillon, Blachot, Wapstra. [http://amdc.in2p3.fr/web/nubase_en.html The Nubase2003 evaluation of nuclear and decay properties] , Nuc. Phys. A 729, pp. 3-128 (2003).
** National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the [http://www.nndc.bnl.gov/nudat2/ NuDat 2.1 database] (retrieved Sept. 2005).
** David R. Lide (ed.), Norman E. Holden in "CRC Handbook of Chemistry and Physics, 85th Edition", online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.See also
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