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Isotopes of Terbium

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

Content
Atomic properties
Decay properties
NMR active nuclides
Radiation protection
References
Terbium isotopes

All atomic nuclei of the chemical element terbium are summarized under terbium isotopes; these all consist of an atomic nucleus with 65 protons and, in the uncharged state, 65 electrons. The difference between the individual terbium isotopes is based on the number of neutrons in the nucleus.

Terbium is a chemical element from the group of rare earth metals and lanthanides. The natural earthly terbium consists of only one stable nuclide, terbium-159.

So far, more than 30 other terbium isotopes and several nuclear isomers have been artificially produced and characterized, all of which are unstable.

The research deals with the beta emitter terbium-161 as a radiotherapeutic: The nuclide, which decays with a half-life of approx. 7 days, could be produced in the purity required for clinical use by neutron irradiation of gadolinium-160.

 

Isotope Table: Terbium

The two following tables list the most important data and properties of the Terbium isotopes. Further information on the individual Terbium 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
Terbium-13513565Tb70134.96476(43) u
[134.9291053 u]
{-32.82585 MeV}		(7/2-)
Terbium-13613665Tb71
Terbium-13713765Tb72
Terbium-13813865Tb73137.95312(32) u
[137.9174653 u]
{-43.66844 MeV}
Terbium-13913965Tb74138.94833(32) u
[138.9126753 u]
{-48.13029 MeV}		139Dy
Terbium-14014065Tb75139.94581(86) u
[139.9101553 u]
{-50.47766 MeV}		(7+)
Terbium-14114165Tb76140.94145(11) u
[140.9057953 u]
{-54.53897 MeV}		(5/2-)141Dy
Terbium-141m141m65Tb76140.94145(11) u
[140.9057953 u]
{-54.53897 MeV}
Terbium-14214265Tb77141.93928(75) u
[141.9036253 u]
{-56.56032 MeV}		1+142Dy
Terbium-142m1142m165Tb77141.93928(75) u
[141.9036253 u]
{-56.56032 MeV}		5-
Terbium-142m2142m265Tb77141.93928(75) u
[141.9036253 u]
{-56.56032 MeV}		8+
Terbium-14314365Tb78142.93514(5) u
[142.8994853 u]
{-60.4167 MeV}		(11/2-)
Terbium-14414465Tb79143.93304(3) u
[143.8973853 u]
{-62.37284 MeV}		1+144Dy
Terbium-144m1144m165Tb79143.93304(3) u
[143.8973853 u]
{-62.37284 MeV}		(6-)
Terbium-144m2144m265Tb79143.93304(3) u
[143.8973853 u]
{-62.37284 MeV}		(8-)
Terbium-144m3144m365Tb79143.93304(3) u
[143.8973853 u]
{-62.37284 MeV}		(9+)
Terbium-144m4144m465Tb79143.93304(3) u
[143.8973853 u]
{-62.37284 MeV}		(10+)
Terbium-14514565Tb80144.92873(12) u
[144.8930753 u]
{-66.38758 MeV}		(3/2+)145Dy
Terbium-145m145m65Tb80144.92873(12) u
[144.8930753 u]
{-66.38758 MeV}		(11/2-)
Terbium-14614665Tb81145.92725(5) u
[145.8915953 u]
{-67.76619 MeV}		1+146Dy
Terbium-146m1146m165Tb81145.92725(5) u
[145.8915953 u]
{-67.76619 MeV}		5-
Terbium-146m2146m265Tb81145.92725(5) u
[145.8915953 u]
{-67.76619 MeV}		10+
Terbium-14714765Tb82146.924055(9) u
[146.8884003 u]
{-70.74231 MeV}		(1/2+)147Dy
151Ho
Terbium-147m147m65Tb82146.924055(9) u
[146.8884003 u]
{-70.74231 MeV}		(11/2-)
Terbium-14814865Tb83147.924275(13) u
[147.8886203 u]
{-70.53738 MeV}		2-148Dy
152Ho
Terbium-148m148m65Tb83147.924275(13) u
[147.8886203 u]
{-70.53738 MeV}		(9)+
Terbium-14914965Tb84148.923254(4) u
[148.8875993 u]
{-71.48844 MeV}		1/2+149Dy
153Ho
Terbium-149m149m65Tb84148.923254(4) u
[148.8875993 u]
{-71.48844 MeV}		11/2-
Terbium-15015065Tb85149.923665(8) u
[149.8880103 u]
{-71.10559 MeV}		(2)-150Dy
154Ho
Terbium-150m150m65Tb85149.923665(8) u
[149.8880103 u]
{-71.10559 MeV}		9+
Terbium-15115165Tb86150.923109(4) u
[150.8874543 u]
{-71.62351 MeV}		1/2(+)151Dy
Terbium-151m151m65Tb86150.923109(4) u
[150.8874543 u]
{-71.62351 MeV}		(11/2-)
Terbium-15215265Tb87151.92408(4) u
[151.8884253 u]
{-70.71902 MeV}		2-152Dy
Terbium-152m152m65Tb87151.92408(4) u
[151.8884253 u]
{-70.71902 MeV}		8+
Terbium-15315365Tb88152.923442(4) u
[152.8877873 u]
{-71.31332 MeV}		5/2+153Dy
Terbium-153m153m65Tb88152.923442(4) u
[152.8877873 u]
{-71.31332 MeV}		11/2-
Terbium-15415465Tb89153.92468(5) u
[153.8890253 u]
{-70.16013 MeV}		0
Terbium-154m1154m165Tb89153.92468(5) u
[153.8890253 u]
{-70.16013 MeV}		3-
Terbium-154m2154m265Tb89153.92468(5) u
[153.8890253 u]
{-70.16013 MeV}		7-
Terbium-15515565Tb90154.923510(11) u
[154.8878553 u]
{-71.24998 MeV}		3/2+155Dy
Terbium-15615665Tb91155.924754(4) u
[155.8890993 u]
{-70.0912 MeV}		3-
Terbium-156m1156m165Tb91155.924754(4) u
[155.8890993 u]
{-70.0912 MeV}		(7-)
Terbium-156m2156m265Tb91155.924754(4) u
[155.8890993 u]
{-70.0912 MeV}		(0+)
Terbium-15715765Tb92156.9240323(13) u
[156.8883776 u]
{-70.76346 MeV}		3/2+157Dy
Terbium-15815865Tb93157.9254202(15) u
[157.8897655 u]
{-69.47064 MeV}		3-
Terbium-158m1158m165Tb93157.9254202(15) u
[157.8897655 u]
{-69.47064 MeV}		0-
Terbium-158m2158m265Tb93157.9254202(15) u
[157.8897655 u]
{-69.47064 MeV}		7-
Terbium-15915965Tb94158.92535(2) u
[158.8896953 u]
{-69.53603 MeV}		3/2+159Dy
159Gd
Terbium-16016065Tb95159.9271748(14) u
[159.8915201 u]
{-67.83624 MeV}		3-
Terbium-16116165Tb96160.9275768(13) u
[160.8919221 u]
{-67.46178 MeV}		3/2+161Gd
Terbium-16216265Tb97161.92949(4) u
[161.8938353 u]
{-65.67964 MeV}		1-162Gd
Terbium-16316365Tb98162.930653(4) u
[162.8949983 u]
{-64.59631 MeV}		3/2+163Gd
Terbium-16416465Tb99163.93336(11) u
[163.8977053 u]
{-62.07476 MeV}		(5+)
Terbium-16516565Tb100164.93498(11) u
[164.8993253 u]
{-60.56574 MeV}		(3/2+)
Terbium-16616665Tb101165.9379397(16) u
[165.902285 u]
{-57.8088 MeV}		(2-)166Gd
Terbium-16716765Tb102166.93996(21) u
[166.9043053 u]
{-55.9269 MeV}		(3/2+)
Terbium-16816865Tb103167.94340(32) u
[167.9077453 u]
{-52.72256 MeV}		(4-)
Terbium-16916965Tb104168.94597(32) u
[168.9103153 u]
{-50.32862 MeV}		(3/2+)
Terbium-17017065Tb105169.94984(43) u
[169.9141853 u]
{-46.72374 MeV}
Terbium-17117165Tb106170.95273(54) u
[170.9170753 u]
{-44.03172 MeV}
Terbium-17217265Tb107171.95722(54) u
[171.9215653 u]
{-39.84931 MeV}		(6+)

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
Tb-1350.94 msp → 134Gd
EC/β+ → 135Gd		ca. 100 %
?		11.56(57) MeV
AL
Tb-136- ungelistet -AL
Tb-137- ungelistet -AL
Tb-138200 nsEC/β+ → 138Gd100 %12.13(36) MeVAL
Tb-1391.6(2) sEC/β+ → 139Gd
EC, p → 138Eu
p → 138Gd		> 0 %
?
?		9.50(36) MeV

AL
Tb-1402.29(15) s&spsilon; → 140Gd
EC, p → 139Eu		99.74 %
0.26 %		11.30(80) MeV
AL
Tb-1413.5(2) sEC/β+ → 141Gd100 %8.68(11) MeVAL
Tb-141m7.9(6) sEC/β+ → 141Gd100 %AL
Tb-142597(17) msEC/β+ → 142Gd
β+, p → 141Eu		> 99 %
<< 1%		10.40(70) MeV
AL
Tb-142m1303(17) msIso → 142Tb100 %AL
Tb-142m226(1) μsIso → 142Tb100 %AL
Tb-14312(1) sEC/β+ → 143Gd100 %7.81(21) MeVAL
Tb-1441 sEC/β+ → 144Gd100 %9.39(4) MeVAL
Tb-144m14.25(15) sEC/β+ → 144Gd
Iso → 144Tb		34 %
66 %
AL
Tb-144m22.8(3) μsAL
Tb-144m30.67(6) μsAL
Tb-144m4300 nsAL
Tb-145AL
Tb-145m30.9(6) sEC/β+ → 145Gd100 %AL
Tb-1468(4) sEC/β+ → 146Gd100 %8.32(5) MeVAL
Tb-146m124.1(5) sEC/β+ → 146Gd100 %AL
Tb-146m21.20(3) msIso → 146Tb100 %AL
Tb-1471.64(3) hEC/β+ → 147Gd100 %4.614(8) MeVAL
Tb-147m1.83(6) minEC/β+ → 147Gd100 %AL
Tb-14860(1) minEC/β+ → 148Gd100 %5.732(13) MeVAL
Tb-148m2.20(5) minEC/β+ → 148Gd100 %AL
Tb-1494.118(25) hEC/β+ → 149Gd
α → 145Eu		83.3(17) %
16.7(17) %		3.638(5) MeV
4.0779(22) MeV		AL
Tb-149m4.16(4) minEC/β+ → 149Gd
α → 145Eu		99.978(3) %
0.022(3) %
AL
Tb-1503.48(16) hEC/β+ → 150Gd
α → 146Eu		> 99.95 %
< 0.05 %		4.658(10) MeV
3.587(5) MeV		AL
Tb-150m5.8(2) minEC/β+ → 150Gd100 %AL
Tb-15117.609(14) hEC/β+ → 151Gd
α → 147Eu		99.9905(15) %
0.0095(13) %		2.565(5) MeV
3.496(4) MeV		AL
Tb-151m25(3) sIso → 151Tb
EC/β+ → 151Gd		93.4(20) %
6.6(20) %
AL
Tb-15217.5(1) hEC/β+ → 152Gd
α → 148Eu		> 99 %
<< 1 %		3.99(4) MeV
3.16(4) MeV		AL
Tb-152m4.2(1) minEC/β+ → 152Gd
Iso → 152Tb		21.1(6) %
78.9(6) %
AL
Tb-1532.34(1) dEC/β+ → 153Gd100 %1.569(4) MeVAL
Tb-153m186(4) μsIso → 153Tb100 %AL
Tb-15421.5(4) hEC/β+ → 154Gd
β- → 154Dy		99.9 %
0.1 %		3.55(5) MeV
0.24(5) MeV		AL
Tb-154m19.4(4) hEC/β+ → 154Gd
β- → 154Dy
Iso → 154Tb		78.2(7) %
< 0.1 %
21.8(7) %

AL
Tb-154m222.7(5) hEC/β+ → 154Gd
Iso → 154Tb		98.2(6) %
1.8(6) %
AL
Tb-1555.32(6) dEC → 155Gd100 %0.82(1) MeVAL
Tb-1565.35(10) dEC/β+ → 156Gd100 %2.444(4) MeVAL
Tb-156m124.4(10) hIso → 156Tb100 %AL
Tb-156m25.3(2) hEC/β+ → 156Gd
Iso → 156Tb		> 0 %
< 100 %
AL
Tb-15771(7) aEC → 157Gd100 %0.060(17) MeVAL
Tb-158180(11) aEC/β+ → 158Gd
β- → 158Dy		83.4(7) %
16.6(7) %		1.2189(18) MeV
0.9367(25) MeV		AL
Tb-158m110.70(17) sIso → 158Tb
β- → 158Dy
β+ → 158Gd		99.39 %
0.6 %
0.01 %

AL
Tb-158m20.40(4) msIso → 158Tb100 %AL
Tb-159stableAL
Tb-16072.3(2) dβ- → 160Dy100 %1.8365(12) MeVAL
Tb-1616.934(14) dβ- → 161Dy100 %0.5937(12) MeVAL
Tb-1627.60(15) minβ- → 162Dy100 %2.51(4) MeVAL
Tb-16319.5(3) minβ- → 163Dy100 %1.785(4) MeVAL
Tb-1643.0(1) minβ- → 164Dy100 %3.89(10) MeVAL
Tb-1652.11(10) minβ- → 165Dy100 %3.05(10) MeVAL
Tb-16625.1(21) sβ- → 166Dy100 %4.7757(17) MeVAL
Tb-16719.4(27) sβ- → 167Dy100 %4.0(2) MeVAL
Tb-1688.2(13) sβ- → 168Dy100 %5.84(33) MeVAL
Tb-1695.1(3) sβ- → 169Dy
β-, n → 168Dy		100 %
?		5.27(42) MeV
0.16(33) MeV		AL
Tb-1700.96(8) sβ- → 170Dy
β-, n → 169Dy		100 %
?		6.94(45) MeV
0.8(5) MeV		AL
Tb-1711.24 sβ- → 171Dy
β-, n → 170Dy		100 %
?		6.16(58) MeV
1.56(54) MeV		AL
Tb-1720.76(19) sβ- → 172Dy
β-, n → 171Dy		100 %
?		8.16(58) MeV
2.27(58) 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 Terbium 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 Terbium 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 Terbium 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)
159Tb
100 %
3/2+		+ 2,014(4)6,4306
{+ 1,432(8)}		10,230,06945
1,2019

1) Quantity Percentage of natural occurrence.

2) Gyromagnetic ratio: 107 rad T-1 s-1
    Quadrupole moment: Q [barn] = [100 fm2]

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 Terbium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Tb-147106 Bq10 Bq/g1.7 h
Tb-149106 Bq10 Bq/g4.1 h
Tb-150106 Bq10 Bq/g3.5 h
Tb-151106 Bq10 Bq/g17.6 h
Tb-153107 Bq100 Bq/g2.3 d
Tb-154106 Bq10 Bq/g21.5 h
Tb-155107 Bq100 Bq/g5.3 d
Tb-156106 Bq10 Bq/g5.2 d
Tb-156m107 Bq1000 Bq/g5.3 h
Tb-157107 Bq100 Bq/g20 TBq99.0 a
Tb-158106 Bq0,1 Bq/g0,09 TBq180.0 a
Tb-160106 Bq1 Bq/g0,06 TBq1 Bq cm-272.3 d
Tb-161106 Bq1000 Bq/g6.9 d

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

 

Literature Sources and References

Properties of the Terbium 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.

Terbium: NMR properties - 159Tb-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] - Silvia Lehenberger et al.:
The low-energy β- and electron emitter 161Tb as an alternative to 177Lu for targeted radionuclide therapy.
In: Nuclear Medicine and Biology, (2011), DOI 10.1016/j.nucmedbio.2011.02.007.

[10] - 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.

 

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