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Isotopes of Tantalum

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

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

All atomic nuclei of the chemical element tantalum are summarized under tantalum isotopes; these all consist of an atomic nucleus with 73 protons and, in the uncharged state, 73 electrons. The difference between each isotope of tantalum is based on the number of neutrons in the nucleus.

 

Naturally Occurring Tantalum Isotopes

In nature, the chemical element tantalum occurs as a mixture of two isotopes, the stable tantalum-181 and - exceptionally - the presumably unstable tantalum-180m. 180mTa is a so-called metastable core isomer, which is in a higher-energy, excited state compared to 180Ta (ground state) and has a far longer half-life. Tantalum-180m is the only natural isotope with these properties.

Atomic Mass maQuantityHalf-lifeSpin
Tantalum
Isotopic mixture		180,94788 u100 %
Isotope 180Ta179,9474684(21) u0,01201(32) %7.1 × 1015 a9-
Isotope 181Ta180,94800(2) u99,98799(32) %stable7/2+

 

All other known and characterized tantalum nuclides are unstable.

 

Isotope Table: Tantalum

The two following tables list the most important data and properties of the Tantalum isotopes. Further information on the individual Tantalum 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
Tantalum-15515573Ta82154.97431(32) u
[154.9342676 u]
{-23.93008 MeV}		11/2-
Tantalum-15615673Ta83155.97209(32) u
[15597208.959958 u]
{14528561287.182 MeV}		(2-)160Re
156W
Tantalum-156m156m73Ta83155.97224(32) u
[155.9321976 u]
{-25.85827 MeV}		9+
Tantalum-15715773Ta84156.96823(16) u
[156.9281876 u]
{-29.59356 MeV}		1/2+161Re
Tantalum-157m1157m173Ta84156.96823(16) u
[156.9281876 u]
{-29.59356 MeV}		11/2-
Tantalum-157m2157m273Ta84156.96823(16) u
[156.9281876 u]
{-29.59356 MeV}		(25/2-)
Tantalum-15815873Ta85157.96654(21) u
[157.9264976 u]
{-31.16779 MeV}		(2-)162Re
Tantalum-158m158m73Ta85157.96654(21) u
[157.9264976 u]
{-31.16779 MeV}		(9+)
Tantalum-158m2158m273Ta85157.96654(21) u
[157.9264976 u]
{-31.16779 MeV}		(19-)
Tantalum-15915973Ta86158.963028(21) u
[158.9229856 u]
{-34.4392 MeV}		1/2+163Re
Tantalum-159m159m73Ta86158.963028(21) u
[158.9229856 u]
{-34.4392 MeV}		11/2-
Tantalum-16016073Ta87159.96154(6) u
[159.9214976 u]
{-35.82526 MeV}		164Re
Tantalum-160m160m73Ta87159.96154(6) u
[159.9214976 u]
{-35.82526 MeV}
Tantalum-16116173Ta88160.958369(26) u
[160.9183266 u]
{-38.77903 MeV}		(1/2+)165Re
Tantalum-16216273Ta89161.95729(6) u
[161.9172476 u]
{-39.78411 MeV}		166Re
Tantalum-16316373Ta90162.95434(4) u
[162.9142976 u]
{-42.53202 MeV}		167Re
Tantalum-16416473Ta91163.95353(3) u
[163.9134876 u]
{-43.28653 MeV}		(3+)168Re
164W
Tantalum-16516573Ta92164.95078(15) u
[164.9107376 u]
{-45.84813 MeV}		(9/2-)169Re
165W
Tantalum-16616673Ta93165.95051(3) u
[165.9104676 u]
{-46.09964 MeV}		(2)+166W
Tantalum-16716773Ta94166.94809(3) u
[166.9080476 u]
{-48.35385 MeV}		(3/2+)167W
Tantalum-16816873Ta95167.94805(3) u
[167.9080076 u]
{-48.39111 MeV}		(2-,3+)168W
Tantalum-16916973Ta96168.94601(3) u
[168.9059676 u]
{-50.29136 MeV}		(5/2+)
Tantalum-17017073Ta97169.94617(3) u
[169.9061276 u]
{-50.14232 MeV}		(3+)170W
Tantalum-17117173Ta98170.94448(3) u
[170.9044376 u]
{-51.71655 MeV}		(5/2-)171W
Tantalum-17217273Ta99171.94489(3) u
[171.9048476 u]
{-51.33463 MeV}		(3+)172W
Tantalum-17317373Ta100172.94375(3) u
[172.9037076 u]
{-52.39654 MeV}		5/2-173W
Tantalum-17417473Ta101173.94445(3) u
[173.9044076 u]
{-51.74449 MeV}		3+174W
Tantalum-17517573Ta102174.94374(3) u
[174.9036976 u]
{-52.40585 MeV}		7/2+175W
Tantalum-17617673Ta103175.94486(3) u
[175.9048176 u]
{-51.36258 MeV}		(1)-176W
Tantalum-17717773Ta104176.944482(4) u
[176.9044396 u]
{-51.71468 MeV}		7/2+177W
Tantalum-17817873Ta105177.94568(6) u
[177.9056376 u]
{-50.59875 MeV}		7-178W
Tantalum-17917973Ta106178.9459392(16) u
[178.9058968 u]
{-50.35731 MeV}		7/2+179W
Tantalum-18018073Ta107179.9474684(21) u
[179.907426 u]
{-48.93287 MeV}		1+180Hf
Tantalum-180m180m73Ta107179.9474684(21) u
[179.907426 u]
{-48.93287 MeV}		9-
Tantalum-18118173Ta108180.94800(2) u
[180.9079576 u]
{-48.43769 MeV}		7/2+181Hf
181W
Tantalum-18218273Ta109181.9501554(15) u
[181.910113 u]
{-46.42995 MeV}		3-182Hf
Tantalum-182m182m73Ta109181.9501554(15) u
[181.910113 u]
{-46.42995 MeV}		5+
Tantalum-182m2182m273Ta109181.9501554(15) u
[181.910113 u]
{-46.42995 MeV}		10-
Tantalum-18318373Ta110182.9513762(15) u
[182.9113338 u]
{-45.29278 MeV}		7/2+183Hf
Tantalum-18418473Ta111183.954010(28) u
[183.9139676 u]
{-42.83941 MeV}		(5-)184Hf
Tantalum-18518573Ta112184.955561(15) u
[184.9155186 u]
{-41.39466 MeV}		(7/2+)185Hf
Tantalum-18618673Ta113185.95855(6) u
[185.9185076 u]
{-38.61043 MeV}		(2-,3-)186Hf
Tantalum-18718773Ta114186.96039(6) u
[186.9203476 u]
{-36.89648 MeV}
Tantalum-18818873Ta115187.96392(6) u
[187.9238776 u]
{-33.6083 MeV}		(1-)
Tantalum-18918973Ta116188.96583(21) u
[188.9257876 u]
{-31.82915 MeV}		(7/2+)
Tantalum-19019073Ta117189.96939(21) u
[189.9293476 u]
{-28.51303 MeV}
Tantalum-19119173Ta118190.97156(32) u
[190.9315176 u]
{-26.49169 MeV}
Tantalum-19219273Ta119191.97524(43) u
[191.9351976 u]
{-23.06379 MeV}		(1,2)
Tantalum-19319373Ta120192.97759(43) u
[192.9375476 u]
{-20.87478 MeV}
Tantalum-19419473Ta121193.98143(54) u
[193.9413876 u]
{-17.29784 MeV}

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
Ta-1552.9 msp → 154Hf100 %AL
Ta-156333 msEC/β+ → 156Hf
p → 155Hf		29(3) %
71(3) %		11.96(33) MeV
AL
Ta-156m0.36(4) sEC/β+ → 156Hf
p → 155Hf		95.8(9) %
4.2(9) %
Ta-15710.1(4) msα → 153Lu
p → 156Hf		96.6(12) %
3.4(12) %		6.355(6) MeV
AL
Ta-157m14.3(1) msα → 153Lu100 %
Ta-157m21.7(1) msα → 153Lu100 %
Ta-15855(15) msα → 154Lu
EC/β+ → 158Hf		91 %
9 %		6.124(4) MeV
10.94(20) MeV		AL
Ta-158m36.7(15) msα → 154Lu
EC/β+ → 158Hf		95(5) %
5(5) %
Ta-158m26.1(1) μsIso → 158Ta
α → 154Lu		98.6(2) %
1.4(2) %
Ta-1590.83(18) sα → 155Lu
EC/β+ → 159Hf		34(5) %
66(5) %		5.681(6) MeV
8.413(26) MeV		AL
Ta-159m0.56(6) sα → 155Lu
EC/β+ → 159Hf		55(1) %
45(1) %
Ta-1601.55(4) sα → 156Lu
EC/β+ → 160Hf		34 %
66 %		5.451(5) MeV
10.12(6) MeV		AL
Ta-160m1.7(2) sα → 156Lu?
Ta-161α → 157Lu
EC/β+ → 161Hf		?
?
AL
Ta-1623.57(12) sα → 158Lu
EC/β+ → 162Hf
EC, p ? 		0.074(10) %
99.926(10) %
5.01(5) MeV
9.39(5) MeV
AL
Ta-16310.6(18) sα → 159Lu
EC/β+ → 163Hf		ca. 0.2 %
ca. 99.8 %		4.749(5) MeV
6.73(5) MeV		AL
Ta-16414.2(3) sEC/β+ → 164Hf
α ? 		100 %
8.54(3) MeV
AL
Ta-16531.0(15) sEC/β+ → 165Hf100 %5.79(3) MeVAL
Ta-16634.4(5) sEC/β+ → 166Hf100 %7.76(4) MeVAL
Ta-16780(4) sEC/β+ → 167Hf100 %5.12(4) MeVAL
Ta-1682.0(1) minEC/β+ → 168Hf100 %6.97(4) MeVAL
Ta-1694.9(4) minEC/β+ → 169Hf100 %4.43(4) MeVAL
Ta-1706.76(6) minEC/β+ → 170Hf100 %6.12(4) MeVAL
Ta-17123.3(3) minEC/β+ → 171Hf100 %3.71(4) MeVAL
Ta-17236.8(3) minEC/β+ → 172Hf100 %5.07(4) MeVAL
Ta-1733.14(13) hEC/β+ → 173Hf100 %3.02(4) MeVAL
Ta-1741.14(8) hEC/β+ → 174Hf100 %4.104(28) MeVAL
Ta-17510.5(2) hEC/β+ → 175Hf100 %2.073(28) MeVAL
Ta-1768.09(5) hEC/β+ → 176Hf100 %3.21(3) MeVAL
Ta-17756.36(13) hEC/β+ → 177Hf100 %1.166(4) MeVAL
Ta-1782.36(8) hEC/β+ → 178Hf100 %1.84(5) MeVAL
Ta-1791.82(3) aEC → 179Hf100 %0.1056(20) MeVAL
Ta-1808.154(6) hEC → 180Hf
β- → 180W		85(3) %
15(3) %		0.8465(24) MeV
0.7032(23) MeV		AL
Ta-180m7.1 × 1015 a
Ta-181stableAL
Ta-182114.74(12) dβ- → 182W100 %1.8161(14) MeVAL
Ta-182m283(3) msIso → 182Ta100 %
Ta-182m215.84(10) minIso → 182Ta100 %
Ta-1835.1(1) dβ- → 183W100 %1.0728(14) MeVAL
Ta-1848.7(1) hβ- → 184W100 %2.866(26) MeVAL
Ta-18549.4(15) minβ- → 185W100 %1.993(14) MeVAL
Ta-18610.5(3) minβ- → 186W100 %3.90(6) MeVAL
Ta-187β- → 187W100 %3.01(6) MeVAL
Ta-18819.6(20) sβ- → 188W100 %5.06(6) MeVAL
Ta-189β- → 189W100 %3.79(20) MeVAL
Ta-1905.3(7) sβ- → 190W100 %5.87(20) MeVAL
Ta-191300 nsβ- → 191W?4.68(30) MeVAL
Ta-1922.2(7) sβ- → 192W100 %6.59(45) MeVAL
Ta-193β- → 193W
β-, n → 192W		100 %
?		5.42(45) MeV
0.71(45) MeV
Ta-194160 nsβ- → 194W
β-, n → 193W		?
?		7.23(58) MeV
0.92(54) 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 Tantalum 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 Tantalum 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 Tantalum 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)
180mTa
0,01201(32) %
9-		4,825(11)
{+ 4,95(2)}
181Ta
99,98799(32) %
7/2+		+ 2,3705(7)3,2445
{+ 3,17(2)}		5,16270,03744
2,5464

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 Tantalum radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Ta-172106 Bq10 Bq/g36.8 min
Ta-173106 Bq10 Bq/g3.1 h
Ta-174106 Bq10 Bq/g1.1 h
Ta-175106 Bq10 Bq/g10.5 h
Ta-176106 Bq10 Bq/g8.1 h
Ta-177107 Bq100 Bq/g56.4 h
Ta-178m+106 Bq10 Bq/g2.4 h
Ta-179107 Bq10 Bq/g6 TBq558.0 d
Ta-180107 Bq0,1 Bq/g8.1 h
Ta-180m107 Bq1000 Bq/g1.8 × 1015 a
Ta-182104 Bq0,1 Bq/g0,06 TBq1 Bq cm-2114.7 d
Ta-182m106 Bq100 Bq/g15.8 min
Ta-183+106 Bq100 Bq/g5.1 d
Ta-184106 Bq10 Bq/g8.7 h
Ta-185105 Bq100 Bq/g49.0 min
Ta-186105 Bq10 Bq/g10.5 min

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

 

Literature Sources and References

Properties of the Tantalum 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.

Tantalum: NMR properties - 180mTa-NMR, 181Ta-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] - R. Robinson, M. Thoennessen:
Discovery of tantalum, rhenium, osmium, and iridium isotopes.
In: Atomic Data and Nuclear Data Tables, (2012), DOI 10.1016/j.adt.2011.09.003.

 

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