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Isotopes of europium



Naturally occurring Europium (Eu) is composed of 2 stable isotopes, 151Eu and 153Eu, with 153Eu being the most abundant (52.2% natural abundance). 35 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, and 154Eu with a half-life of 8.593 years. All of the remaining radioactive 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 8 meta states, with the most stable being 150mEu (t½ 12.8 hours), 152m1Eu (t½ 9.3116 hours) and 152m2Eu (t½ 96 minutes).

Additional recommended knowledge

The primary decay mode before the most abundant stable isotope, 153Eu, is electron capture, and the primary mode after is beta minus decay. The primary decay products before 153Eu are isotopes of samarium (Sm) and the primary products after are isotopes of gadolinium (Gd).
Standard atomic mass: 151.964(1) u

Table

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
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
133Eu 63 70 132.94924(32)# 200# ms 11/2-#
134Eu 63 71 133.94651(21)# 0.5(2) s
135Eu 63 72 134.94182(32)# 1.5(2) s 11/2-#
136Eu 63 73 135.93960(21)# 3.3(3) s (7+)
136mEu 0(500)# keV 3.8(3) s (3+)
137Eu 63 74 136.93557(21)# 8.4(5) s 11/2-#
138Eu 63 75 137.93371(3) 12.1(6) s (6-)
139Eu 63 76 138.929792(14) 17.9(6) s (11/2)-
140Eu 63 77 139.92809(6) 1.51(2) s 1+
140mEu 210(15) keV 125(2) ms 5-#
141Eu 63 78 140.924931(14) 40.7(7) s 5/2+
141mEu 96.45(7) keV 2.7(3) s 11/2-
142Eu 63 79 141.92343(3) 2.36(10) s 1+
142mEu 460(30) keV 1.223(8) min 8-
143Eu 63 80 142.920298(12) 2.59(2) min 5/2+
143mEu 389.51(4) keV 50.0(5) µs 11/2-
144Eu 63 81 143.918817(12) 10.2(1) s 1+
144mEu 1127.6(6) keV 1.0(1) µs (8-)
145Eu 63 82 144.916265(4) 5.93(4) d 5/2+
145mEu 716.0(3) keV 490 ns 11/2-
146Eu 63 83 145.917206(7) 4.61(3) d 4-
146mEu 666.37(16) keV 235(3) µs 9+
147Eu 63 84 146.916746(3) 24.1(6) d 5/2+
148Eu 63 85 147.918086(11) 54.5(5) d 5-
149Eu 63 86 148.917931(5) 93.1(4) d 5/2+
150Eu 63 87 149.919702(7) 36.9(9) a 5(-)
150mEu 42.1(5) keV 12.8(1) h 0-
151Eu 63 88 150.9198502(26) STABLE 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) a 3-
152m1Eu 45.5998(4) keV 9.3116(13) h 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 63 90 152.9212303(26) STABLE 5/2+ 0.5219(6)
154Eu 63 91 153.9229792(26) 8.593(4) a 3-
154m1Eu 145.3(3) keV 46.3(4) min (8-)
154m2Eu 68.1702(4) keV 2.2(1) µs 2+
155Eu 63 92 154.9228933(27) 4.7611(13) a 5/2+
156Eu 63 93 155.924752(6) 15.19(8) d 0+
157Eu 63 94 156.925424(6) 15.18(3) h 5/2+
158Eu 63 95 157.92785(8) 45.9(2) min (1-)
159Eu 63 96 158.929089(8) 18.1(1) min 5/2+
160Eu 63 97 159.93197(22)# 38(4) s 1(-)
161Eu 63 98 160.93368(32)# 26(3) s 5/2+#
162Eu 63 99 161.93704(32)# 10.6(10) s
163Eu 63 100 162.93921(54)# 6# s 5/2+#
164Eu 63 101 163.94299(64)# 2# s
165Eu 63 102 164.94572(75)# 1# s 5/2+#
166Eu 63 103 165.94997(86)# 400# ms
167Eu 63 104 166.95321(86)# 200# ms 5/2+#

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 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 Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and 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. 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 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.


Isotopes of samarium Isotopes of europium Isotopes of gadolinium
Index to isotope pages
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_europium". A list of authors is available in Wikipedia.
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