Naturally occurring europium (63Eu) is composed of two isotopes, 151Eu and 153Eu, with 153Eu being the most abundant (52.2% natural abundance). While 153Eu is observationally stable (theoretically can undergo alpha decay with half-life over 5.5×1017 years), 151Eu was found in 2007 to be unstable and undergo alpha decay.[4] The half-life is measured to be (4.62 ± 0.95(stat.) ± 0.68(syst.)) × 1018 years[5] which corresponds to 1 alpha decay per two minutes in every kilogram of natural europium. Besides the natural radioisotope 151Eu, 36 artificial radioisotopes have been characterized, with the most stable being 150Eu with a half-life of 36.9 years, 152Eu with a half-life of 13.516 years, 154Eu with a half-life of 8.593 years, and 155Eu with a half-life of 4.7612 years. The majority of the remaining radioactive isotopes, which range from 130Eu to 170Eu, have half-lives that are less than 12.2 seconds. This element also has 18 metastable isomers, with the most stable being 150mEu (t1/2 12.8 hours), 152m1Eu (t1/2 9.3116 hours) and 152m5Eu (t1/2 96 minutes).
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| Standard atomic weight Ar°(Eu) | |||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
The primary decay mode before the most abundant stable isotope, 153Eu, is electron capture, and the primary mode after is beta decay. The primary decay products before 153Eu are isotopes of samarium and the primary products after are isotopes of gadolinium.
List of isotopes
edit
| Nuclide [n 1] |
Z | N | Isotopic mass (Da) [n 2][n 3] |
Half-life [n 4][n 5] |
Decay mode [n 6] |
Daughter isotope [n 7][n 8] |
Spin and parity [n 9][n 5] |
Natural abundance (mole fraction) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Excitation energy[n 5] | Normal proportion | Range of variation | |||||||||||||||||
| 130Eu | 63 | 67 | 129.96357(54)# | 1.1(5) ms [0.9( 5−3) ms] |
2 # | ||||||||||||||
| 131Eu | 63 | 68 | 130.95775(43)# | 17.8(19) ms | 3/2 | ||||||||||||||
| 132Eu | 63 | 69 | 131.95437(43)# | 100# ms | β | 132Sm | |||||||||||||
| p | 131Sm | ||||||||||||||||||
| 133Eu | 63 | 70 | 132.94924(32)# | 200# ms | β | 133Sm | 11/2−# | ||||||||||||
| 134Eu | 63 | 71 | 133.94651(21)# | 0.5(2) s | β | 134Sm | |||||||||||||
| β , p (rare) | 133Pm | ||||||||||||||||||
| 135Eu | 63 | 72 | 134.94182(32)# | 1.5(2) s | β | 135Sm | 11/2−# | ||||||||||||
| β , p | 134Pm | ||||||||||||||||||
| 136Eu | 63 | 73 | 135.93960(21)# | 3.3(3) s | β (99.91%) | 136Sm | (7 ) | ||||||||||||
| β , p (.09%) | 135Pm | ||||||||||||||||||
| 136mEu | 0(500)# keV | 3.8(3) s | β (99.91%) | 136Sm | (3 ) | ||||||||||||||
| β , p (.09%) | 135Pm | ||||||||||||||||||
| 137Eu | 63 | 74 | 136.93557(21)# | 8.4(5) s | β | 137Sm | 11/2−# | ||||||||||||
| 138Eu | 63 | 75 | 137.93371(3) | 12.1(6) s | β | 138Sm | (6−) | ||||||||||||
| 139Eu | 63 | 76 | 138.929792(14) | 17.9(6) s | β | 139Sm | (11/2)− | ||||||||||||
| 140Eu | 63 | 77 | 139.92809(6) | 1.51(2) s | β (95.1(7)%) | 140Sm | 1 | ||||||||||||
| EC (4.9(7)%) | |||||||||||||||||||
| 140mEu | 210(15) keV | 125(2) ms | IT (99%) | 140Eu | 5−# | ||||||||||||||
| β (1%) | 140Sm | ||||||||||||||||||
| 141Eu | 63 | 78 | 140.924931(14) | 40.7(7) s | β | 141Sm | 5/2 | ||||||||||||
| 141mEu | 96.45(7) keV | 2.7(3) s | IT (86%) | 141Eu | 11/2− | ||||||||||||||
| β (14%) | 141Sm | ||||||||||||||||||
| 142Eu | 63 | 79 | 141.92343(3) | 2.36(10) s | β (89.9(16)%) | 142Sm | 1 | ||||||||||||
| EC (11.1(16)%) | |||||||||||||||||||
| 142mEu | 460(30) keV | 1.223(8) min | β | 142Sm | 8− | ||||||||||||||
| 143Eu | 63 | 80 | 142.920298(12) | 2.59(2) min | β | 143Sm | 5/2 | ||||||||||||
| 143mEu | 389.51(4) keV | 50.0(5) μs | 11/2− | ||||||||||||||||
| 144Eu | 63 | 81 | 143.918817(12) | 10.2(1) s | β | 144Sm | 1 | ||||||||||||
| 144mEu | 1127.6(6) keV | 1.0(1) μs | (8−) | ||||||||||||||||
| 145Eu | 63 | 82 | 144.916265(4) | 5.93(4) d | β | 145Sm | 5/2 | ||||||||||||
| 145mEu | 716.0(3) keV | 490 ns | 11/2− | ||||||||||||||||
| 146Eu | 63 | 83 | 145.917206(7) | 4.61(3) d | β | 146Sm | 4− | ||||||||||||
| 146mEu | 666.37(16) keV | 235(3) μs | 9 | ||||||||||||||||
| 147Eu | 63 | 84 | 146.916746(3) | 24.1(6) d | β (99.99%) | 147Sm | 5/2 | ||||||||||||
| α (.0022%) | 143Pm | ||||||||||||||||||
| 148Eu | 63 | 85 | 147.918086(11) | 54.5(5) d | β (100%) | 148Sm | 5− | ||||||||||||
| α (9.39×10−7%) | 144Pm | ||||||||||||||||||
| 149Eu | 63 | 86 | 148.917931(5) | 93.1(4) d | EC | 149Sm | 5/2 | ||||||||||||
| 150Eu | 63 | 87 | 149.919702(7) | 36.9(9) y | β | 150Sm | 5(−) | ||||||||||||
| 150mEu | 42.1(5) keV | 12.8(1) h | β− (89%) | 150Gd | 0− | ||||||||||||||
| β (11%) | 150Sm | ||||||||||||||||||
| IT (≤5×10−8%)[6] | 150Eu | ||||||||||||||||||
| 151Eu[n 10] | 63 | 88 | 150.9198502(26) | 4.62×1018 y | α | 147Pm | 5/2 | 0.4781(6) | |||||||||||
| 151mEu | 196.245(10) keV | 58.9(5) μs | IT[7] | 151Eu | 11/2− | ||||||||||||||
| 152Eu | 63 | 89 | 151.9217445(26) | 13.537(6) y | EC (72.09%) | 152Sm | 3− | ||||||||||||
| β− (27.9%) | 152Gd | ||||||||||||||||||
| β (0.027%) | 152Sm | ||||||||||||||||||
| 152m1Eu | 45.5998(4) keV | 9.3116(13) h | β− (72%) | 152Gd | 0− | ||||||||||||||
| β (28%) | 152Sm | ||||||||||||||||||
| 152m2Eu | 65.2969(4) keV | 0.94(8) μs | 1− | ||||||||||||||||
| 152m3Eu | 78.2331(4) keV | 165(10) ns | 1 | ||||||||||||||||
| 152m4Eu | 89.8496(4) keV | 384(10) ns | 4 | ||||||||||||||||
| 152m5Eu | 147.86(10) keV | 96(1) min | 8− | ||||||||||||||||
| 153Eu[n 11] | 63 | 90 | 152.9212303(26) | Observationally Stable[n 12][8][9] | 5/2 | 0.5219(6) | |||||||||||||
| 154Eu[n 11] | 63 | 91 | 153.9229792(26) | 8.593(4) y | β− (99.98%) | 154Gd | 3− | ||||||||||||
| EC (.02%) | 154Sm | ||||||||||||||||||
| 154m1Eu | 68.1702(4) keV | 2.2(1) μs | IT | 154Eu | 2 | ||||||||||||||
| 154m2Eu | 145.3(3) keV | 46.3(4) min | IT | 154Eu | (8−) | ||||||||||||||
| 155Eu[n 11] | 63 | 92 | 154.9228933(27) | 4.7611(13) y | β− | 155Gd | 5/2 | ||||||||||||
| 156Eu[n 11] | 63 | 93 | 155.924752(6) | 15.19(8) d | β− | 156Gd | 0 | ||||||||||||
| 157Eu | 63 | 94 | 156.925424(6) | 15.18(3) h | β− | 157Gd | 5/2 | ||||||||||||
| 158Eu | 63 | 95 | 157.92785(8) | 45.9(2) min | β− | 158Gd | (1−) | ||||||||||||
| 159Eu | 63 | 96 | 158.929089(8) | 18.1(1) min | β− | 159Gd | 5/2 | ||||||||||||
| 160Eu | 63 | 97 | 159.93197(22)# | 38(4) s | β− | 160Gd | 1(−) | ||||||||||||
| 161Eu | 63 | 98 | 160.93368(32)# | 26(3) s | β− | 161Gd | 5/2 # | ||||||||||||
| 162Eu | 63 | 99 | 161.93704(32)# | 10.6(10) s | β− | 162Gd | |||||||||||||
| 163Eu | 63 | 100 | 162.93921(54)# | 7.7(4) s | β− | 163Gd | 5/2 # | ||||||||||||
| 163mEu | 964.5(10) keV | 911(24) ns | (13/2−) | ||||||||||||||||
| 164Eu | 63 | 101 | 163.94299(64)# | 4.16(19) s | β− | 164Gd | |||||||||||||
| 165Eu | 63 | 102 | 164.94572(75)# | 2.163 0.139 −0.120 s[10] |
β− | 165Gd | 5/2 # | ||||||||||||
| 166Eu | 63 | 103 | 165.94997(86)# | 1.277 0.100 −0.145 s[10] |
β− (99.37%) | 166Gd | |||||||||||||
| β−, n (0.63%) | 165Gd | ||||||||||||||||||
| 167Eu | 63 | 104 | 166.95321(86)# | 852 76 −54 ms[10] |
β− (98.05%) | 167Gd | 5/2 # | ||||||||||||
| β−, n (1.95%) | 166Gd | ||||||||||||||||||
| 168Eu | 63 | 105 | 440 48 −47 ms[10] |
β− (96.05%) | 168Gd | ||||||||||||||
| β−, n (3.95%) | 167Gd | ||||||||||||||||||
| 169Eu | 63 | 106 | 389 92 −88 ms[10] |
β− (85.38%) | 169Gd | ||||||||||||||
| β−, n (14.62%) | 168Gd | ||||||||||||||||||
| 170Eu | 63 | 107 | 197 74 −71 ms[10] |
β− | 170Gd | ||||||||||||||
| β−, n | 169Gd | ||||||||||||||||||
| This table header & footer: | |||||||||||||||||||
- ^ mEu – Excited nuclear isomer.
- ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
- ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
- ^ Bold half-life – nearly stable, half-life longer than age of universe.
- ^ a b c # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^
Modes of decay:
EC: Electron capture IT: Isomeric transition
p: Proton emission - ^ Bold italics symbol as daughter – Daughter product is nearly stable.
- ^ Bold symbol as daughter – Daughter product is stable.
- ^ ( ) spin value – Indicates spin with weak assignment arguments.
- ^ primordial radionuclide
- ^ a b c d Fission product
- ^ Believed to undergo α decay to 149Pm with a half-life over 5.5×1017 years
Europium-155
edit| t½ (year) |
Yield (%) |
Q (keV) |
βγ | |
|---|---|---|---|---|
| 155Eu | 4.76 | 0.0803 | 252 | βγ |
| 85Kr | 10.76 | 0.2180 | 687 | βγ |
| 113mCd | 14.1 | 0.0008 | 316 | β |
| 90Sr | 28.9 | 4.505 | 2826 | β |
| 137Cs | 30.23 | 6.337 | 1176 | βγ |
| 121mSn | 43.9 | 0.00005 | 390 | βγ |
| 151Sm | 94.6 | 0.5314 | 77 | β |
Europium-155 is a fission product with a half-life of 4.76 years. It has a maximum decay energy of 252 keV. In a thermal reactor (almost all current nuclear power plants), it has a low fission product yield, about half of one percent as much as the most abundant fission products.
155Eu's large neutron capture cross section (about 3900 barns for thermal neutrons, 16000 resonance integral) means that most of even the small amount produced is destroyed in the course of the nuclear fuel's burnup. Yield, decay energy, and half-life are all far less than that of 137Cs and 90Sr, so 155Eu is not a significant contributor to nuclear waste.
Some 155Eu is also produced by successive neutron capture on 153Eu (nonradioactive, 350 barns thermal, 1500 resonance integral, yield is about 5 times as great as 155Eu) and 154Eu (half-life 8.6 years, 1400 barns thermal, 1600 resonance integral, fission yield is extremely small because beta decay stops at 154Sm). However, the differing cross sections mean that both 155Eu and 154Eu are destroyed faster than they are produced.
154Eu is a prolific emitter of gamma radiation.[11]
| Isotope | Half-life | Relative yield | Thermal neutron | Resonance integral |
|---|---|---|---|---|
| Eu-153 | Stable | 5 | 350 | 1500 |
| Eu-154 | 8.6 years | Nearly 0 | 1500 | 1600 |
| Eu-155 | 4.76 years | 1 | 3900 | 16000 |
References
edit- ^ 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.
- ^ "Standard Atomic Weights: Europium". CIAAW. 1995.
- ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
- ^ Belli, P.; et al. (2007). "Search for α decay of natural europium". Nuclear Physics A. 789 (1–4): 15–29. Bibcode:2007NuPhA.789...15B. doi:10.1016/j.nuclphysa.2007.03.001.1–4&rft.pages=15-29&rft.date=2007&rft_id=info:doi/10.1016/j.nuclphysa.2007.03.001&rft_id=info:bibcode/2007NuPhA.789...15B&rft.aulast=Belli&rft.aufirst=P.&rft.au=Bernabei, R&rft.au=Cappella, F&rft.au=Cerulli, R&rft.au=Dai, C&rft.au=Danevich, F&rft.au=Dangelo, A&rft.au=Incicchitti, A&rft.au=Kobychev, V&rft.au=Nagorny, S.S.&rft.au=Nisi, S.&rft.au=Nozzoli, F.&rft.au=Prosperi, D.&rft.au=Tretyak, V.I.&rft.au=Yurchenko, S.S.&rfr_id=info:sid/en.wikipedia.org:Isotopes of europium" class="Z3988">
- ^ Casali, N.; Nagorny, S. S.; Orio, F.; Pattavina, L.; et al. (2014). "Discovery of the 151Eu α decay". Journal of Physics G: Nuclear and Particle Physics. 41 (7): 075101. arXiv:1311.2834. Bibcode:2014JPhG...41g5101C. doi:10.1088/0954-3899/41/7/075101. S2CID 116920467.
- ^ "Adopted Levels for 150Eu" (PDF). NNDC Chart of Nuclides.
- ^ "Adopted Levels for 151Eu". NNDC Chart of Nuclides.
- ^ Danevich, F. A.; Andreotti, E.; Hult, M.; Marissens, G.; Tretyak, V. I.; Yuksel, A. (2012). "Search for α decay of 151Eu to the first excited level of 147Pm using underground γ-ray spectrometry". European Physical Journal A. 48 (157): 157. arXiv:1301.3465. Bibcode:2012EPJA...48..157D. doi:10.1140/epja/i2012-12157-7. S2CID 118657922.
- ^ Belli, P.; Bernabei, R.; Danevich, F. A.; et al. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (8): 140–1–140–7. arXiv:1908.11458. Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. ISSN 1434-601X. S2CID 201664098.
- ^ a b c d e f Kiss, G. G.; Vitéz-Sveiczer, A.; Saito, Y.; et al. (2022). "Measuring the β-decay properties of neutron-rich exotic Pm, Sm, Eu, and Gd isotopes to constrain the nucleosynthesis yields in the rare-earth region". The Astrophysical Journal. 936 (107): 107. Bibcode:2022ApJ...936..107K. doi:10.3847/1538-4357/ac80fc. hdl:2117/375253.
- ^ "Archived copy" (PDF). Archived from the original (PDF) on 2011-07-06. Retrieved 2011-04-02.
{{cite web}}: CS1 maint: archived copy as title (link)
- Isotope masses from:
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.0013-128&rft.date=2003&rft_id=info:doi/10.1016/j.nuclphysa.2003.11.001&rft_id=info:bibcode/2003NuPhA.729....3A&rft.aulast=Audi&rft.aufirst=Georges&rft.au=Bersillon, Olivier&rft.au=Blachot, Jean&rft.au=Wapstra, Aaldert Hendrik&rft_id=https://hal.archives-ouvertes.fr/in2p3-00020241/document&rfr_id=info:sid/en.wikipedia.org:Isotopes of europium" class="Z3988">
- Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.683-800&rft.date=2003&rft_id=info:doi/10.1351/pac200375060683&rft.aulast=de Laeter&rft.aufirst=John Robert&rft.au=Böhlke, John Karl&rft.au=De Bièvre, Paul&rft.au=Hidaka, Hiroshi&rft.au=Peiser, H. Steffen&rft.au=Rosman, Kevin J. R.&rft.au=Taylor, Philip D. P.&rft_id=https://doi.org/10.1351%2Fpac200375060683&rfr_id=info:sid/en.wikipedia.org:Isotopes of europium" class="Z3988">
- Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.2051-2066&rft.date=2006&rft_id=info:doi/10.1351/pac200678112051&rft.aulast=Wieser&rft.aufirst=Michael E.&rft_id=https://doi.org/10.1351%2Fpac200678112051&rfr_id=info:sid/en.wikipedia.org:Isotopes of europium" class="Z3988">
- "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
- Half-life, spin, and isomer data selected from the following sources.
- Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.0013-128&rft.date=2003&rft_id=info:doi/10.1016/j.nuclphysa.2003.11.001&rft_id=info:bibcode/2003NuPhA.729....3A&rft.aulast=Audi&rft.aufirst=Georges&rft.au=Bersillon, Olivier&rft.au=Blachot, Jean&rft.au=Wapstra, Aaldert Hendrik&rft_id=https://hal.archives-ouvertes.fr/in2p3-00020241/document&rfr_id=info:sid/en.wikipedia.org:Isotopes of europium" class="Z3988">
- National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
- Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.