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Isotopes of Samarium

List, data and properties of all known isotopes of Samarium.


Content

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

The two following tables list the most important data and properties of the Samarium isotopes. Further information on the individual Samarium isotopes is listed on separate pages and can be accessed via the link in column 1.

 

Atomic Properties

Isotope
Nuclide
ENAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
Parent
123456
Samarium-12812862Sm66127.95808(54) u
[127.9240707 u]
{-39.04823 MeV}
0+
Samarium-12912962Sm67128.95491(54) u
[128.9209007 u]
{-42.00106 MeV}
(1/2+,3/2+)
Samarium-13013062Sm68129.94900(43) u
[129.9149907 u]
{-47.50619 MeV}
0+130Eu
Samarium-13113162Sm69130.94618(43) u
[130.9121707 u]
{-50.13301 MeV}
5/2+~131Eu
Samarium-13213262Sm70131.94087(32) u
[131.9068607 u]
{-55.07924 MeV}
0+132Eu
Samarium-13313362Sm71132.93856(32) u
[132.9045507 u]
{-57.23099 MeV}
(5/2+)133Eu
Samarium-13413462Sm72133.93411(21) u
[133.9001007 u]
{-61.37614 MeV}
0+134Eu
Samarium-13513562Sm73134.93252(17) u
[134.8985107 u]
{-62.85722 MeV}
(3/2+,5/2+)135Eu
Samarium-135m135m62Sm73134.93252(17) u
[134.8985107 u]
{-62.85722 MeV}
Samarium-13613662Sm74135.928276(13) u
[135.8942667 u]
{-66.81048 MeV}
0+136Eu
Samarium-136m136m62Sm74135.928276(13) u
[135.8942667 u]
{-66.81048 MeV}
(8-)
Samarium-13713762Sm75136.92697(5) u
[136.8929607 u]
{-68.02701 MeV}
(9/2-)137Eu
Samarium-137m137m62Sm75136.92697(5) u
[136.8929607 u]
{-68.02701 MeV}
(1/2+)
Samarium-13813862Sm76137.923244(13) u
[137.8892347 u]
{-71.49775 MeV}
0+138Eu
Samarium-13913962Sm77138.922297(12) u
[138.8882877 u]
{-72.37988 MeV}
1/2+139Eu
Samarium-139m139m62Sm77138.922297(12) u
[138.8882877 u]
{-72.37988 MeV}
11/2-
Samarium-14014062Sm78139.918995(13) u
[139.8849857 u]
{-75.45567 MeV}
0+140Eu
Samarium-14114162Sm79140.918482(9) u
[140.8844727 u]
{-75.93353 MeV}
1/2+141Eu
Samarium-141m141m62Sm79140.918482(9) u
[140.8844727 u]
{-75.93353 MeV}
11/2-
Samarium-14214262Sm80141.915205(3) u
[141.8811957 u]
{-78.98603 MeV}
0+142Eu
Samarium-14314362Sm81142.914635(3) u
[142.8806257 u]
{-79.51699 MeV}
3/2+143Eu
Samarium-143m1143m162Sm81142.914635(3) u
[142.8806257 u]
{-79.51699 MeV}
11/2-
Samarium-143m2143m262Sm81142.914635(3) u
[142.8806257 u]
{-79.51699 MeV}
23/2(-)
Samarium-14414462Sm82143.91201(2) u
[143.8780007 u]
{-81.96216 MeV}
0+144Eu
144Pm
148Gd
Samarium-144m144m62Sm82143.91201(2) u
[143.8780007 u]
{-81.96216 MeV}
6+
Samarium-14514562Sm83144.9134172(17) u
[144.8794079 u]
{-80.65136 MeV}
7/2-145Eu
149Gd
Samarium-145m145m62Sm83144.9134172(17) u
[144.8794079 u]
{-80.65136 MeV}
(49/2+)
Samarium-14614662Sm84145.913047(3) u
[145.8790377 u]
{-80.9962 MeV}
0+146Eu
146Pm
150Gd
Samarium-14714762Sm85146.91490(2) u
[146.8808907 u]
{-79.27014 MeV}
7/2-147Eu
147Pm
Samarium-14814862Sm86147.91483(2) u
[147.8808207 u]
{-79.33534 MeV}
0+148Eu
148Pm
152Gd
Samarium-14914962Sm87148.91719(2) u
[148.8831807 u]
{-77.13702 MeV}
7/2-149Eu
149Pm
Samarium-15015062Sm88149.91728(2) u
[149.8832707 u]
{-77.05318 MeV}
0+150Eu
150Pm
150Nd
Samarium-15115162Sm89150.9199391(14) u
[150.8859298 u]
{-74.57625 MeV}
5/2-151Pm
Samarium-151m151m62Sm89150.9199391(14) u
[150.8859298 u]
{-74.57625 MeV}
(11/2)-
Samarium-15215262Sm90151.91974(2) u
[151.8857307 u]
{-74.76171 MeV}
0+152Pm
152Eu
Samarium-15315362Sm91152.9221036(11) u
[152.8880943 u]
{-72.56003 MeV}
3/2+153Pm
Samarium-153m153m62Sm91152.9221036(11) u
[152.8880943 u]
{-72.56003 MeV}
11/2-
Samarium-15415462Sm92153.92222(2) u
[153.8882107 u]
{-72.4516 MeV}
0+154Pm
154Eu
Samarium-15515562Sm93154.9246471(16) u
[154.8906378 u]
{-70.19077 MeV}
3/2-155Pm
Samarium-15615662Sm94155.925539(9) u
[155.8915297 u]
{-69.35997 MeV}
0+156Pm
Samarium-156m156m62Sm94155.925539(9) u
[155.8915297 u]
{-69.35997 MeV}
5-
Samarium-15715762Sm95156.928419(5) u
[156.8944097 u]
{-66.67727 MeV}
(3/2-)157Pm
Samarium-15815862Sm96157.929951(5) u
[157.8959417 u]
{-65.25022 MeV}
0+158Pm
Samarium-15915962Sm97158.933217(6) u
[158.8992077 u]
{-62.20796 MeV}
5/2-159Pm
Samarium-16016062Sm98159.935335(6) u
[159.9013257 u]
{-60.23506 MeV}
0+160Pm
Samarium-16116162Sm99160.939160(7) u
[160.9051507 u]
{-56.67209 MeV}
(7/2+)161Pm
Samarium-16216262Sm100161.94146(21) u
[161.9074507 u]
{-54.52966 MeV}
0+162Pm
Samarium-16316362Sm101162.94555(32) u
[162.9115407 u]
{-50.71985 MeV}
(1/2-)163Pm
Samarium-16416462Sm102163.94836(32) u
[163.9143507 u]
{-48.10235 MeV}
0+
Samarium-16516562Sm103164.95297(43) u
[164.9189607 u]
{-43.80816 MeV}
(5/2-)
Samarium-16616662Sm104165.95627(43) u
[165.9222607 u]
{-40.73423 MeV}
0+

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
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) μsAL
Sm-13745(1) sEC/β+137Pm100 %6.05(4) MeVAL
Sm-137m20 sEC/β+137PmAL
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) %

AL
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) %

AL
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) %

AL
Sm-143m230(3) msIso → 143Sm100 %AL
Sm-144stableAL
Sm-144m880(25) nsAL
Sm-145340(3) dEC → 145Pm100 %0.616(3) MeVAL
Sm-145m0.96 μsIso → 145Sm100 %AL
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 %AL
Sm-152stableAL
Sm-15346.284(4) hβ-153Eu100 %0.8074(7) MeVAL
Sm-153m10.6(3) msIso → 153Sm100 %AL
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) nsAL
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 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - 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.
5 - nuclear spin I, unit: h/2π.
6 - 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.

7 - isotope notation in short form.
8 - decay: half-live of the Samarium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: 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.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - 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
{Quadrupole moment}
Resonant
frequency
v0 bei 1 T
Relative
sensitivity
H0 = const.
v0 = const. 3)
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) Gyromagnetic ratio: 107 rad T-1 s-1
    Quadrupole moment: Q fm-2

3) 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.

 


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Last update: 2022-12-12


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