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Isotopes of Samarium

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

 

Samarium isotopes

All atomic nuclei of the chemical element samarium are summarized under samarium isotopes; these all consist of an atomic nucleus with 62 protons and, in the uncharged state, 62 electrons. The difference between each samarium isotope is based on the number of neutrons in the nucleus.

 

Naturally Occurring Samarium Isotopes

Samarium, a chemical element from the group of rare earth metals, occurs naturally in a large number of isotopes, 5 of which are considered stable and 3 of which have half-lives of many millions of years.

Atomic Mass maQuantityHalf-lifeSpin
Samarium
Isotopic mixture
150,36 u100 %
Isotope 144Sm143,91201(2) u3,08(4) %stable0+
Isotope 146Sm145,913047(3) utraces6.8(7) × 107 a0+
Isotope 147Sm146,91490(2) u15,00(14) %1.060(11) × 1011 a7/2-
Isotope 148Sm147,91483(2) u11,25(9) %7(3)×1015 a0+
Isotope 149Sm148,91719(2) u13,82(10) %stable7/2-
Isotope 150Sm149,91728(2) u7,37(9) %stable0+
Isotope 152Sm151,91974(2) u26,74(9) %stable0+
Isotope 154Sm153,92222(2) u22,74(14) %stable0+

 

All other samarium nuclides are unstable and decay, emitting radioactive radiation.

 

Nuclear medicine

The samarium nuclide 153Sm Application as anti-inflammatory radiotherapeutic agent [153Sm]samarium hydroxyapatite colloid (ATC code V10AX02) and as [153Sm]samarium lexidronam (V10BX02) for pain relief in bone metastases.

 

Isotope Table: Samarium

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
128Sm6212866Samarium-128127.95808(54) u
[127.9240707 u]
{-39.04823 MeV}
0+
129Sm6212967Samarium-129128.95491(54) u
[128.9209007 u]
{-42.00106 MeV}
(1/2+,3/2+)
130Sm6213068Samarium-130129.94900(43) u
[129.9149907 u]
{-47.50619 MeV}
0+130Eu
131Sm6213169Samarium-131130.94618(43) u
[130.9121707 u]
{-50.13301 MeV}
5/2+~131Eu
132Sm6213270Samarium-132131.94087(32) u
[131.9068607 u]
{-55.07924 MeV}
0+132Eu
133Sm6213371Samarium-133132.93856(32) u
[132.9045507 u]
{-57.23099 MeV}
(5/2+)133Eu
134Sm6213472Samarium-134133.93411(21) u
[133.9001007 u]
{-61.37614 MeV}
0+134Eu
135Sm6213573Samarium-135134.93252(17) u
[134.8985107 u]
{-62.85722 MeV}
(3/2+,5/2+)135Eu
135mSm6213573Samarium-135m134.93252(17) u
[134.8985107 u]
{-62.85722 MeV}
136Sm6213674Samarium-136135.928276(13) u
[135.8942667 u]
{-66.81048 MeV}
0+136Eu
136mSm6213674Samarium-136m135.928276(13) u
[135.8942667 u]
{-66.81048 MeV}
(8-)
137Sm6213775Samarium-137136.92697(5) u
[136.8929607 u]
{-68.02701 MeV}
(9/2-)137Eu
137mSm6213775Samarium-137m136.92697(5) u
[136.8929607 u]
{-68.02701 MeV}
(1/2+)
138Sm6213876Samarium-138137.923244(13) u
[137.8892347 u]
{-71.49775 MeV}
0+138Eu
139Sm6213977Samarium-139138.922297(12) u
[138.8882877 u]
{-72.37988 MeV}
1/2+- 0.53(2)139Eu
139mSm6213977Samarium-139m138.922297(12) u
[138.8882877 u]
{-72.37988 MeV}
11/2-1.1(2)
140Sm6214078Samarium-140139.918995(13) u
[139.8849857 u]
{-75.45567 MeV}
0+140Eu
141Sm6214179Samarium-141140.918482(9) u
[140.8844727 u]
{-75.93353 MeV}
1/2+-0.74(2)141Eu
141mSm6214179Samarium-141m140.918482(9) u
[140.8844727 u]
{-75.93353 MeV}
11/2-+0.84(2)
142Sm6214280Samarium-142141.915205(3) u
[141.8811957 u]
{-78.98603 MeV}
0+142Eu
143Sm6214381Samarium-143142.914635(3) u
[142.8806257 u]
{-79.51699 MeV}
3/2++1.01(2)143Eu
143m1Sm6214381Samarium-143m1142.914635(3) u
[142.8806257 u]
{-79.51699 MeV}
11/2-+ 1.01
143m2Sm6214381Samarium-143m2142.914635(3) u
[142.8806257 u]
{-79.51699 MeV}
23/2(-)
144Sm6214482Samarium-144143.91201(2) u
[143.8780007 u]
{-81.96216 MeV}
0+144Eu
144Pm
148Gd
144mSm6214482Samarium-144m143.91201(2) u
[143.8780007 u]
{-81.96216 MeV}
6+
145Sm6214583Samarium-145144.9134172(17) u
[144.8794079 u]
{-80.65136 MeV}
7/2-- 1.12145Eu
149Gd
145mSm6214583Samarium-145m144.9134172(17) u
[144.8794079 u]
{-80.65136 MeV}
(49/2+)
146Sm6214684Samarium-146145.913047(3) u
[145.8790377 u]
{-80.9962 MeV}
0+146Eu
146Pm
150Gd
147Sm6214785Samarium-147146.91490(2) u
[146.8808907 u]
{-79.27014 MeV}
7/2-- 0.8149147Eu
147Pm
148Sm6214886Samarium-148147.91483(2) u
[147.8808207 u]
{-79.33534 MeV}
0+148Eu
148Pm
152Gd
149Sm6214987Samarium-149148.91719(2) u
[148.8831807 u]
{-77.13702 MeV}
7/2-- 0.6718149Eu
149Pm
150Sm6215088Samarium-150149.91728(2) u
[149.8832707 u]
{-77.05318 MeV}
0+150Eu
150Pm
150Nd
151Sm6215189Samarium-151150.9199391(14) u
[150.8859298 u]
{-74.57625 MeV}
5/2-- 0.363151Pm
151mSm6215189Samarium-151m150.9199391(14) u
[150.8859298 u]
{-74.57625 MeV}
(11/2)-
152Sm6215290Samarium-152151.91974(2) u
[151.8857307 u]
{-74.76171 MeV}
0+152Pm
152Eu
153Sm6215391Samarium-153152.9221040(13) u
[152.8880947 u]
{-72.55966 MeV}
3/2+- 0.00216153Pm
153mSm6215391Samarium-153m152.9221040(13) u
[152.8880947 u]
{-72.55966 MeV}
11/2-
154Sm6215492Samarium-154153.92222(2) u
[153.8882107 u]
{-72.4516 MeV}
0+154Pm
154Eu
155Sm6215593Samarium-155154.9246471(16) u
[154.8906378 u]
{-70.19077 MeV}
3/2-1.13(13)155Pm
156Sm6215694Samarium-156155.925539(9) u
[155.8915297 u]
{-69.35997 MeV}
0+156Pm
156mSm6215694Samarium-156m155.925539(9) u
[155.8915297 u]
{-69.35997 MeV}
5-
157Sm6215795Samarium-157156.928419(5) u
[156.8944097 u]
{-66.67727 MeV}
(3/2-)157Pm
158Sm6215896Samarium-158157.929951(5) u
[157.8959417 u]
{-65.25022 MeV}
0+158Pm
159Sm6215997Samarium-159158.933217(6) u
[158.8992077 u]
{-62.20796 MeV}
5/2-159Pm
160Sm6216098Samarium-160159.935335(6) u
[159.9013257 u]
{-60.23506 MeV}
0+160Pm
161Sm6216199Samarium-161160.939160(7) u
[160.9051507 u]
{-56.67209 MeV}
(7/2+)161Pm
162Sm62162100Samarium-162161.94146(21) u
[161.9074507 u]
{-54.52966 MeV}
0+162Pm
163Sm62163101Samarium-163162.94555(32) u
[162.9115407 u]
{-50.71985 MeV}
(1/2-)163Pm
164Sm62164102Samarium-164163.94836(32) u
[163.9143507 u]
{-48.10235 MeV}
0+
165Sm62165103Samarium-165164.95297(43) u
[164.9189607 u]
{-43.80816 MeV}
(5/2-)
166Sm62166104Samarium-166165.95627(43) u
[165.9222607 u]
{-40.73423 MeV}
0+

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
Sm-1280.5 sAL
Sm-1290.55(10) sEC/β+129Pm
EC, p → 128Nd
< 100 %
> 0 %
10.88(58) MeV
AL
Sm-1301 sEC/β+130Pm?7.89(45) MeVAL
Sm-1311.2(2) sEC/β+131Pm
EC, p → 130Nd
100 %
?
9.53(45) MeV
AL
Sm-1324.0(3) sEC/β+132Pm
EC, p → 131Nd
100 %
?
6.55(33) MeV
AL
Sm-1332.89(16) sEC/β+133Pm
EC, p → 132Nd
100 %
?
8.818(30) MeV
AL
Sm-1349.5(8) sEC/β+134Pm100 %5.36(20) MeVAL
Sm-13510.3(5) sEC/β+135Pm
EC, p → 134Nd
99.98 %
0.02(1) %
7.19(17) MeV
AL
Sm-135m2.4(9) sβ+135PmAL
Sm-13647(2) sEC/β+136Pm100 %4.36(7) MeVAL
Sm-136m15(1) μs2264.7(11) keVAL
Sm-13745(1) sEC/β+137Pm100 %6.05(4) MeVAL
Sm-137m20 sEC/β+137Pm180(50) keVAL
Sm-1383.1(2) minEC/β+138Pm100 %3.44(3) MeVAL
Sm-1392.57(10) minEC/β+139Pm100 %5.120(17) MeVAL
Sm-139m10.7(6) sIso → 139Sm
EC/β+139Pm
97.7(5) %
6.3(5) %

457.38(23) keVAL
Sm-14014.82(12) minEC/β+140Pm100 %2.758(27) MeVAL
Sm-14110.2(2) minEC/β+141Pm100 %4.589(16) MeVAL
Sm-141m22.6(2) minEC/β+141Pm
Iso → 141Sm
99.69(3) %
0.31(3) %

175.9(3) keVAL
Sm-14272.49(5) minEC/β+142Pm100 %2.156(24) MeVAL
Sm-1438.75(6) minEC/β+143Pm100 %3.443(4) MeVAL
Sm-143m166(2) sIso → 143Sm
β+143Pm
99.76(5) %
0.24(5) %

753.99(16) keVAL
Sm-143m230(3) msIso → 143Sm100 %2793.8(13) keVAL
Sm-144stableAL
Sm-144m880(25) ns2323.60(8) keVAL
Sm-145340(3) dEC → 145Pm100 %0.616(3) MeVAL
Sm-145m0.96 μsIso → 145Sm100 %8786.2(7) keVAL
Sm-1466.8(7) × 107 aα → 142Nd100 %2.5288(28) MeVAL
Sm-1471.060(11) × 1011 aα → 143Nd100 %2.3110(3) MeVAL
Sm-1487(3)×1015 aα → 144Nd100 %1.9868(4) MeVAL
Sm-149stableAL
Sm-150stableAL
Sm-15190(8) aβ-151Eu100 %0.0766(5) MeVAL
Sm-151m1.4(1) μsIso → 151Sm100 %261.13(4) keVAL
Sm-152stableAL
Sm-15346.284(4) hβ-153Eu100 %0.8075(7) MeVAL
Sm-153m10.6(3) msIso → 153Sm100 %98.37(10) keVAL
Sm-154stableAL
Sm-15522.3(2) minβ-155Eu100 %1.6273(12) MeVAL
Sm-1569.4(2) hβ-156Eu100 %0.722(8) MeVAL
Sm-156m185(7) ns1397.55(9) keVAL
Sm-1578.03(7) minβ-157Eu100 %2.781(6) MeVAL
Sm-1585.30(3) minβ-158Eu100 %2.005(10) MeVAL
Sm-15911.37(15) sβ-159Eu100 %3.836(7) MeVAL
Sm-1609.6(3) sβ-160Eu100 %3.246(11) MeVAL
Sm-1614.8(4) sβ-161Eu100 %5.120(12) MeVAL
Sm-1622.4(5) sβ-162Eu100 %4.17(20) MeVAL
Sm-1631.23 sβ-163Eu
β-, n → 162Eu
100 %
?
5.76(30) MeV
AL
Sm-1641.43(24) sβ-164Eu
β-, n → 163Eu
100 %
?
5.28(32) MeV
0.31(30) MeV
AL
Sm-1650.98(21) sβ-165Eu
β-, n → 164Eu
100 %
?
6.92(42) MeV
1.50(42) MeV
AL
Sm-1660.80(63) sβ-166Eu
β-, n → 165Eu
100 %
?
6.48(54) MeV
1.92(42) 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 Samarium isotope.
6 - Relative atomic mass of the Samarium 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 Samarium 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 Samarium 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)
147Sm
15,00(14) %
7/2-
- 0,81491,1124- 25,9(26)1,77480,00152
0,8754
149Sm
13,82(10) %
7/2-
- 0,67180,9175+ 7,5(7)1,46310,00085
0,7216

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 Samarium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Sm-141105 Bq10 Bq/g10.2 min
Sm-141m+106 Bq10 Bq/g22.6 min
Sm-142+107 Bq100 Bq/g72.5 min
Sm-145107 Bq10 Bq/g340.0 d
Sm-146105 Bq1 Bq/g1 × 108 a
Sm-147104 Bq1 Bq/gUnbegrenzt (UL)1.1 × 1011 a
Sm-151108 Bq1000 Bq/g500 TBq100 Bq cm-290.0 a
Sm-153106 Bq100 Bq/g2 TBq10 Bq cm-246.3 h
Sm-155106 Bq100 Bq/g22.3 min
Sm-156106 Bq100 Bq/g9.4 h

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

 

Literature Sources and References

Properties of the Samarium 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.

Samarium: NMR properties - 147Sm-NMR, 149Sm-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] - N. Kinoshita et al:
A Shorter 146Sm Half-Life Measured and Implications for 146Sm-142Nd Chronology in the Solar System.
In: Science, (2012), DOI 10.1126/science.1215510.

 


Category: Isotopes

Last update: 05.07.2020



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