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Isotopes of Europium

List, data and properties of all known isotopes of Europium as well as radioactive decay products and intermediate products.

 

Europium isotopes

All atomic nuclei of the chemical element europium are summarized under europium isotopes; these all consist of an atomic nucleus with 63 protons and, in the uncharged state, 63 electrons. The difference between each europium isotope is based on the number of neutrons in the nucleus.

 

Naturally Occurring Europium Isotopes

Europium is a chemical element from the group of rare earth metals (see under rare earths).

Natural occurrences of europium consist of 2 nuclides, the stable europium-153 and the radioisotope europium-151.

Atomic Mass maQuantityHalf-lifeSpin
Europium
Isotopic mixture
151,964 u100 %
Isotope 151Eu150,9198569(14) u47,81(6) %1.7 × 1018 a5/2+
Isotope 153Eu152,92124(2) u52,19(6) %stable5/2+

 

In addition, more than 30 other europium isotopes and a whole series of nuclear isomers have been characterized, all of which are unstable and are listed in the following isotope table:

 

Isotope Table: Europium

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
130Eu6313067Europium-130129.96384(54) u
[129.9292822 u]
{-33.68282 MeV}
(1+)
131Eu6313168Europium-131130.95784(43) u
[130.9232822 u]
{-39.27179 MeV}
3/2+
132Eu6313269Europium-132131.95470(43) u
[131.9201422 u]
{-42.19668 MeV}
(0)
133Eu6313370Europium-133132.94924(32) u
[132.9146822 u]
{-47.28264 MeV}
11/2-
134Eu6313471Europium-134133.94640(32) u
[133.9118422 u]
{-49.92808 MeV}
135Eu6313572Europium-135134.94187(21) u
[134.9073122 u]
{-54.14775 MeV}
11/2-
136Eu6313673Europium-136135.93962(21) u
[135.9050622 u]
{-56.24361 MeV}
(7+)
136mEu6313673Europium-136m135.93962(21) u
[135.9050622 u]
{-56.24361 MeV}
(3+)
137Eu6313774Europium-137136.935431(5) u
[136.9008732 u]
{-60.14564 MeV}
(11/2-)
138Eu6313875Europium-138137.93371(3) u
[137.8991522 u]
{-61.74874 MeV}
(6-)5.3(7)138Gd
139Eu6313976Europium-139138.929792(14) u
[138.8952342 u]
{-65.39833 MeV}
(11/2)-6.1(8)139Gd
139mEu6313976Europium-139m138.929792(14) u
[138.8952342 u]
{-65.39833 MeV}
(7/2+)
140Eu6314077Europium-140139.92809(6) u
[139.8935322 u]
{-66.98373 MeV}
1++ 1.365(13)140Gd
140mEu6314077Europium-140m139.92809(6) u
[139.8935322 u]
{-66.98373 MeV}
(5-)
141Eu6314178Europium-141140.924932(14) u
[140.8903742 u]
{-69.92539 MeV}
5/2++ 3.494(8)141Gd
141mEu6314178Europium-141m140.924932(14) u
[140.8903742 u]
{-69.92539 MeV}
11/2-
142Eu6314279Europium-142141.92344(3) u
[141.8888822 u]
{-71.31518 MeV}
1++ 1.536(19)142Gd
142mEu6314279Europium-142m141.92344(3) u
[141.8888822 u]
{-71.31518 MeV}
8-+ 2.978(11)
143Eu6314380Europium-143142.920299(12) u
[142.8857412 u]
{-74.241 MeV}
5/2+143Gd
143mEu6314380Europium-143m142.920299(12) u
[142.8857412 u]
{-74.241 MeV}
11/2-
144Eu6314481Europium-144143.918820(12) u
[143.8842622 u]
{-75.61868 MeV}
1++ 1.893(13) MeV144Gd
144mEu6314481Europium-144m143.918817(12) u
[143.8842592 u]
{-75.62148 MeV}
(8-)
145Eu6314582Europium-145144.916273(3) u
[144.8817152 u]
{-77.9912 MeV}
5/2++ 3.993(7)145Gd
149Tb
145mEu6314582Europium-145m144.916273(3) u
[144.8817152 u]
{-77.9912 MeV}
11/2-+ 7.46(5)
146Eu6314683Europium-146145.917211(6) u
[145.8826532 u]
{-77.11746 MeV}
4-+ 1.421(6)146Gd
150Tb
146mEu6314683Europium-146m145.917211(6) u
[145.8826532 u]
{-77.11746 MeV}
9+
147Eu6314784Europium-147146.9167523(2) u
[146.8821945 u]
{-77.54473 MeV}
5/2++ 3.724(8)147Gd
151Tb
147mEu6314784Europium-147m146.9167523(2) u
[146.8821945 u]
{-77.54473 MeV}
+ 7.05(3)
148Eu6314885Europium-148147.918089(11) u
[147.8835312 u]
{-76.29961 MeV}
5-+ 2.340(10)
148mEu6314885Europium-148m147.918089(11) u
[147.8835312 u]
{-76.29961 MeV}
9++ 6.120(45)
149Eu6314986Europium-149148.917937(4) u
[148.8833792 u]
{-76.44119 MeV}
5/2++ 3.565(6)149Gd
149mEu6314986Europium-149m148.917937(4) u
[148.8833792 u]
{-76.44119 MeV}
11/2-+ 6.99(27)
150Eu6315087Europium-150149.919707(7) u
[149.8851492 u]
{-74.79245 MeV}
5-+ 2.708(11)
150mEu6315087Europium-150m149.919707(7) u
[149.8851492 u]
{-74.79245 MeV}
0-
151Eu6315188Europium-151150.9198569(14) u
[150.8852991 u]
{-74.65282 MeV}
5/2++ 3.4717(6)151Gd
151Sm
151mEu6315188Europium-151m150.9198569(14) u
[150.8852991 u]
{-74.65282 MeV}
11/2-
152Eu6315289Europium-152151.9217512(14) u
[151.8871934 u]
{-72.88829 MeV}
3-- 1.9401(8)
152m1Eu6315289Europium-152m1151.9217512(14) u
[151.8871934 u]
{-72.88829 MeV}
0-
152m2Eu6315289Europium-152m2151.9217512(14) u
[151.8871934 u]
{-72.88829 MeV}
1-
153Eu6315390Europium-153152.92124(2) u
[152.8866822 u]
{-73.36447 MeV}
5/2++ 1.5324(3)
153mEu6315390Europium-153m152.92124(2) u
[152.8866822 u]
{-73.36447 MeV}
19/2-
154Eu6315491Europium-154153.9229860(14) u
[153.8884282 u]
{-71.73808 MeV}
3-- 2.005(6)
154m1Eu6315491Europium-154m1153.9229860(14) u
[153.8884282 u]
{-71.73808 MeV}
2+
154m2Eu6315491Europium-154m2153.9229860(14) u
[153.8884282 u]
{-71.73808 MeV}
8-
155Eu6315592Europium-155154.9229001(15) u
[154.8883423 u]
{-71.81809 MeV}
5/2++ 1.520(2)155Sm
156Eu6315693Europium-156155.924763(4) u
[155.8902052 u]
{-70.08281 MeV}
0+156Sm
157Eu6315794Europium-157156.925433(5) u
[156.8908752 u]
{-69.45871 MeV}
5/2++ 1.50(2)157Sm
158Eu6315895Europium-158157.927799(11) u
[157.8932412 u]
{-67.2548 MeV}
(1-)1.44(2)158Sm
252Cf
159Eu6315996Europium-159158.929100(5) u
[158.8945422 u]
{-66.04292 MeV}
5/2+1.38(2)159Sm
160Eu6316097Europium-160159.931851(10) u
[159.8972932 u]
{-63.48038 MeV}
1160Sm
161Eu6316198Europium-161160.933664(11) u
[160.8991062 u]
{-61.79159 MeV}
5/2+161Sm
162Eu6316299Europium-162161.93698(4) u
[161.9024222 u]
{-58.70275 MeV}
162Sm
163Eu63163100Europium-163162.93936(7) u
[162.9048022 u]
{-56.4858 MeV}
5/2+
164Eu63164101Europium-164163.94269(12) u
[163.9081322 u]
{-53.38392 MeV}
(3)
165Eu63165102Europium-165164.94555(15) u
[164.9109922 u]
{-50.71985 MeV}
5/2+
166Eu63166103Europium-166165.94932(38) u
[165.9147622 u]
{-47.20812 MeV}
167Eu63167104Europium-167166.95275(43) u
[166.9181922 u]
{-44.01309 MeV}
(5/2+)
168Eu63168105Europium-168167.95734(54) u
[167.9227822 u]
{-39.73753 MeV}
(6-)

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
Eu-1300.90(+49-29) msp → 129Sm100 %AL
Eu-13117.8(19) msp → 130Sm
EC/β+131Sm
89(9) %
11(9) %

10.86(57) MeV
AL
Eu-132p → 131Sm
EC/β+132Sm
?
?

12.88(50) MeV
AL
Eu-133ungelistetAL
Eu-1340.5(2) sEC/β+134Sm
EC, p 133Pm
100 %
> 0 %
11.45(36) MeV
AL
Eu-1351.5(2) sEC/β+135Sm
EC, p 134Pm
100 %
?
8.71(25) MeV
AL
Eu-1363.3(3) sEC/β+136Sm
β+, p → 135Pm
99.91 %
0.09 %
10.57(20) MeV
AL
Eu-136m3.8(3) sEC/β+136Sm
β+, p → 135Pm
99.91 %
0.09 %

YAL
Eu-13711(2) sEC/β+137Sm100 %7.88(4) MeVAL
Eu-13812.1(6) sEC/β+138Sm100 %9.75(3) MeVAL
Eu-13917.9(6) sEC/β+139Sm100 %6.982(17) MeVAL
Eu-139m10(2) μsIso → 139Eu100 %148.3(3) keV
Eu-1401.51(2) sEC/β+140Sm100 %8.47(5) MeVAL
Eu-140m125(2) msEC/β+140Sm
Iso → 140Eu
< 1 %
> 99 %

210(15) keVAL
Eu-14140.7(7) sEC/β+141Sm100 %6.008(15) MeVAL
Eu-141m2.7(3) sEC/β+141Sm
Iso → 141Eu
13 %
87 %

96.45(7) keVAL
Eu-1422.34(12) sEC/β+142Sm100 %4.35 MeVAL
Eu-142m1.223(8) minEC/β+142Sm100 %460 keVAL
Eu-1432.59(2) minEC/β+143Sm100 %5.276(11) MeVAL
Eu-143m50.0(5) μs389.51(4) keVAL
Eu-14410.2(1) sEC/β+144Sm100 %6.346(11) MeVAL
Eu-144m1.0(1) μs1127.6(6) keVAL
Eu-1455.93(4) dEC/β+145Sm100 %2.66(3) MeVAL
Eu-145m490(30) ns716.0(3) keVAL
Eu-1464.61(3) dEC/β+146Sm100 %3.879(7) MeVAL
Eu-146m235(3) μsIso → 146Eu100 %666.33(11) keVAL
Eu-14724.1(6) dEC → 147Sm
α → 143Pm
99.9978(6) %
0.0022(6) %
1.722(3) MeV
2.991(3) MeV
AL
Eu-147m0.765(15) μs625.27(5) keV
Eu-14854.5(5) dEC/β+148Sm
α → 144Pm
> 99 %
<< 1 %
3.037(10) MeV
2.692(10) MeV
AL
Eu-148m162(8) nsIso → 148Eu100.0 %720.4(3) keV
Eu-14993.1(4) dEC → 149Sm100 %0.695(4) MeVAL
Eu-1492.45(5) μsIso → 149Eu?496.386(2)
Eu-15036.9(9) aEC/β+150Sm100 %2.259(6) MeVAL
Eu-150m12.8(1) hEC/β+151Sm
β-150Gd
Iso → 150Eu
11(2) %
89(2) %
<< 1 %


41.7(10) keVAL
Eu-1511.7 × 1018 aα → 147Pm?1.9645(11) MeVAL
Eu-151m58.9(5) µsIso → 151Eu100 %196.245(10)AL
Eu-15213.517(9) aEC/β+152Sm
β-152Gd
72.08(13) %
27.92(13) %
1.8743(18) MeV
1.8187(7) MeV
AL
Eu-152m19.3116(13) hEC/β+152Sm
β-152Gd
27(3) %
73(3) %

45.5998(4) keVAL
Eu-152m20.94(8) μsIso → 152Eu100 %0.1478 MeV65.2969(4)AL
Eu-153stableAL
Eu-153m475(19) ns1771.0(4) keV
Eu-1548.601(10) aEC/β+154Sm
β-154Gd
0.018(12) %
99.982(12) %
0.717(20) MeV
1.9678(8) MeV
AL
Eu-154m12.2(1) μsIso → 154Eu?68.1702(4) keVAL
Eu-154m246.3(4) minIso → 154Eu100 %145.3(3) keV
Eu-1554.753(14) aβ-155Gd100 %0.2518(9) MeVAL
Eu-15615.19(8) dβ-156Gd100 %2.452(3) MeVAL
Eu-15715.18(3) hβ-157Gd100 %1.365(4) MeVAL
Eu-15845.9(2) minβ-158Gd100 %3.434(10) MeVAL
Eu-15918.1(1) minβ-159Gd100 %2.518(4) MeVAL
Eu-16038(4) sβ-160Gd100 %4.461(10) MeVAL
Eu-16126(3) sβ-161Gd100 %3.714(11) MeVAL
Eu-16210.6(10) sβ-162Gd100 %5.58(3) MeVAL
Eu-1637.7(4) sβ-163Gd100 %4.83(6) MeVAL
Eu-1644.15(20) sβ-164Gd100 %6.39(5) MeVAL
Eu-1652.3(2) sβ-165Gd100 %5.73(6) MeVAL
Eu-1661.7(3) sβ-166Gd
β-, n 165Gd
100 %
?
7.32(30) MeV
1.17(38) MeV
AL
Eu-1671.3(5) sβ-167Gd
β-, n → 166Gd
100 %
?
6.8(5) MeV
2.45(44) MeV
Eu-1680.2(1) sβ-169Gd
β-, n → 168Gd
100 %
?
8.62(64) MeV
3.00(58) MeV

 

Notes (related to the columns):

1 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Europium isotope.
6 - Relative atomic mass of the Europium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
7 - Nuclear spin I, unit: h/2π.
8 - Nuclear magnetic moment μmag.
9 - Source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.
10 - Decay: Half-live of the Europium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
11 - Decay: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
12 - Decay percentage in percent (%).
13 - Decay energy; Particle energy related to decay type.
14 - AE = Excitation energy for metastable nuclei.
15 - Other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

NMR active Europium nuclides

Nuclide
quantity 1)
spin
Nuclear magnetic
moment
μ/μN
Gyromagnetic
ratio
107 rad T-1 s-1
Quadrupole
moment
Q fm-2
Resonant
frequency
v0 bei 1 T
Relative
sensitivity
H0 = const.
v0 = const. 2)
151Eu
47,81(6) %
5/2+
+ 3,4717(6)6,547790,3(10)10,58560,17929
2,9006
153Eu
52,19(6) %
5/2+
+ 1,5324(3)2,9371241,2(21)4,67450,01544
1,2809

1) Quantity Percentage of natural occurrence.

2) Related to 1H = 1,000.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Europium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Eu-145106 Bq10 Bq/g5.9 d
Eu-146106 Bq10 Bq/g4.6 d
Eu-147106 Bq10 Bq/g0,2 TBq24.0 d
Eu-148106 Bq1 Bq/g0,03 TBq54.5 d
Eu-149107 Bq10 Bq/g2 TBq93.1 d
Eu-150106 Bq0,1 Bq/g36.4 d
Eu-152106 Bq0,1 Bq/g0,06 TBq1 Bq cm-213.5 d
Eu-152m106 Bq100 Bq/g0,2 TBq10 Bq cm-29.3 h
Eu-154106 Bq0,1 Bq/g0,06 TBq1 Bq cm-28.6 a
Eu-155107 Bq1 Bq/g2 TBq10 Bq cm-24.8 a
Eu-156106 Bq10 Bq/g15.2 d
Eu-157106 Bq100 Bq/g15.2 h
Eu-158105 Bq10 Bq/g45.9 min

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Europium nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Europium: NMR properties - 151Eu-NMR, 153Eu-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

[9] - E. May, M. Thoennessen:
Discovery of samarium, europium, Dysprosium, and Dysprosium isotopes.
In: Atomic Data and Nuclear Data Tables, (2013), DOI 10.1016/j.adt.2012.01.007.

 


Category: Isotopes

Last update: 05.07.2020



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