Isotopes of europium

Isotopes of europium ( ₆₃Eu)
β ?	152 Gd
Standard atomic weight A r °(Eu)
	151.964 ± 0.001 ; 151.96 ± 0.01 ( abridged ) ;
	view ; talk ; edit ;

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 5.5×10 ¹⁷ 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.)) × 10 ¹⁸ 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 (t _1/2 12.8 hours), ^152m1Eu (t _1/2 9.3116 hours) and ^152m5Eu (t _1/2 96 minutes).

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)
Nuclide ^{[n 1]}	Excitation energy ^{[n 5]}			Half-life ^{[n 4]}^{[n 5]}	Decay mode ^{[n 6]}	Daughter isotope ^{[n 7]}^{[n 8]}	Spin and parity ^{[n 9]}^{[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
¹³²Eu	63	69	131.95437(43)#	100# ms	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
¹³⁴Eu	63	71	133.94651(21)#	0.5(2) s	β ⁺, p (rare)	¹³³Pm
¹³⁵Eu	63	72	134.94182(32)#	1.5(2) s	β ⁺	¹³⁵Sm	11/2?#
¹³⁵Eu	63	72	134.94182(32)#	1.5(2) s	β ⁺, p	¹³⁴Pm	11/2?#
¹³⁶Eu	63	73	135.93960(21)#	3.3(3) s	β ⁺ (99.91%)	¹³⁶Sm	(7+)
¹³⁶Eu	63	73	135.93960(21)#	3.3(3) s	β ⁺, p (.09%)	¹³⁵Pm	(7+)
^136mEu	0(500)# keV			3.8(3) s	β ⁺ (99.91%)	¹³⁶Sm	(3+)
^136mEu	0(500)# keV			3.8(3) s	β ⁺, p (.09%)	¹³⁵Pm	(3+)
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+
¹⁴⁰Eu	63	77	139.92809(6)	1.51(2) s	EC (4.9(7)%)	¹⁴⁰Sm	1+
^140mEu	210(15) keV			125(2) ms	IT (99%)	¹⁴⁰Eu	5?#
^140mEu	210(15) keV			125(2) ms	β ⁺(1%)	¹⁴⁰Sm	5?#
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?
^141mEu	96.45(7) keV			2.7(3) s	β ⁺ (14%)	¹⁴¹Sm	11/2?
¹⁴²Eu	63	79	141.92343(3)	2.36(10) s	β ⁺ (89.9(16)%)	¹⁴²Sm	1+
¹⁴²Eu	63	79	141.92343(3)	2.36(10) s	EC (11.1(16)%)	¹⁴²Sm	1+
^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+
¹⁴⁷Eu	63	84	146.916746(3)	24.1(6) d	α (.0022%)	¹⁴³Pm	5/2+
¹⁴⁸Eu	63	85	147.918086(11)	54.5(5) d	β ⁺ (100%)	¹⁴⁸Sm	5?
¹⁴⁸Eu	63	85	147.918086(11)	54.5(5) d	α (9.39×10 ^?7%)	¹⁴⁴Pm	5?
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%)	¹⁵⁰Eu
¹⁵¹Eu ^{[n 10]}	63	88	150.9198502(26)	4.62×10 ¹⁸ y	α	¹⁴⁷Pm	5/2+	0.4781(6)
^151mEu	196.245(10) keV			58.9(5) μs			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?
^152m1Eu	45.5998(4) keV			9.3116(13) h	β ⁺ (28%)	¹⁵²Sm	0?
^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]}^[6]			5/2+	0.5219(6)
¹⁵⁴Eu ^{[n 11]}	63	91	153.9229792(26)	8.593(4) y	β ^? (99.98%)	¹⁵⁴Gd	3?
¹⁵⁴Eu ^{[n 11]}	63	91	153.9229792(26)	8.593(4) y	EC (.02%)	¹⁵⁴Sm	3?
^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 ^[7]	β ^?	¹⁶⁵Gd	5/2+#
¹⁶⁶Eu	63	103	165.94997(86)#	1.277 +0.100 ?0.145 s ^[7]	β ^? (99.37%)	¹⁶⁶Gd
¹⁶⁶Eu	63	103	165.94997(86)#	1.277 +0.100 ?0.145 s ^[7]	β ^?, n (0.63%)	¹⁶⁵Gd
¹⁶⁷Eu	63	104	166.95321(86)#	852 +76 ?54 s ^[7]	β ^? (98.05%)	¹⁶⁷Gd	5/2+#
¹⁶⁷Eu	63	104	166.95321(86)#	852 +76 ?54 s ^[7]	β ^?, n (1.95%)	¹⁶⁶Gd	5/2+#
¹⁶⁸Eu	63	105		440 +48 ?47 s ^[7]	β ^? (96.05%)	¹⁶⁸Gd
¹⁶⁸Eu	63	105		440 +48 ?47 s ^[7]	β ^?, n (3.95%)	¹⁶⁷Gd
¹⁶⁹Eu	63	106		389 +92 ?88 s ^[7]	β ^? (85.38%)	¹⁶⁹Gd
¹⁶⁹Eu	63	106		389 +92 ?88 s ^[7]	β ^?, n (14.62%)	¹⁶⁸Gd
¹⁷⁰Eu	63	107		197 +74 ?71 s ^[7]	β ^?	¹⁷⁰Gd
¹⁷⁰Eu	63	107		197 +74 ?71 s ^[7]	β ^?, n	¹⁶⁹Gd
This table header & footer: view

^ ^mEu – Excited nuclear isomer .
^ ( ) – Uncertainty (1 σ ) 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 × 10 ¹⁷ years

Europium-155 [ edit ]

Medium-lived
fission products ^{[
further explanation needed
]}
	t _½ ( 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	β γ
^121mSn	43.9	0.00005	390	βγ
¹⁵¹Sm	88.8	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 . ^[8]

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; Bohlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Groning, 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 .
^ 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 .
^ 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 .
^ ^a ^b ^c ^d ^e ^f Kiss, G. G.; Vitez-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 N UBASE evaluation of nuclear and decay properties" , Nuclear Physics A , 729 : 3?128, Bibcode : 2003NuPhA.729....3A , doi : 10.1016/j.nuclphysa.2003.11.001
Isotopic compositions and standard atomic masses from:
- de Laeter, John Robert ; Bohlke, John Karl; De Bievre, 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 .
- 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 .
"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 N UBASE evaluation of nuclear and decay properties" , Nuclear Physics A , 729 : 3?128, Bibcode : 2003NuPhA.729....3A , doi : 10.1016/j.nuclphysa.2003.11.001
- 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 .

[6] Eu – Excited nuclear isomer .

[7] ( ) – Uncertainty (1 σ ) is given in concise form in parentheses after the corresponding last digits.

[TMS-8] # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).

[9] Bold half-life – nearly stable, half-life longer than age of universe .

[TNN-10] # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).

[11] Modes of decay:

EC: Electron capture

IT: Isomeric transition

p: Proton emission

[12] Bold italics symbol as daughter – Daughter product is nearly stable.

[13] Bold symbol as daughter – Daughter product is stable.

[14] ( ) spin value – Indicates spin with weak assignment arguments.

[15] rimordial radionuclide

[FP-16] Fission product

[n12-17] Believed to undergo α decay to ¹⁴⁹Pm with a half-life over 5.5 × 10 ¹⁷ years

[NUBASE2020-1] 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 .

[2] "Standard Atomic Weights: Europium" . CIAAW . 1995.

[CIAAW2021-3] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Bohlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Groning, 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 .

[151Eu-Belli-4] 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 .

[154Eu--5] 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 .

[18] 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 .

[Ln922-19] ^ ^a ^b ^c ^d ^e ^f Kiss, G. G.; Vitez-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 .

[154Eu-nds.ipen.br2011-20] "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 )

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