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Isotopes of Tantalum

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

 

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

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
155Ta7315582Tantalum-155154.97431(32) u
[154.9342676 u]
{-23.93008 MeV}
11/2-
156Ta7315683Tantalum-156155.97224(32) u
[155.9321976 u]
{-25.85827 MeV}
(2-)160Re
156mTa7315683Tantalum-156m155.97224(32) u
[155.9321976 u]
{-25.85827 MeV}
9+
157Ta7315784Tantalum-157156.96823(16) u
[156.9281876 u]
{-29.59356 MeV}
1/2+161Re
157m1Ta7315784Tantalum-157m1156.96823(16) u
[156.9281876 u]
{-29.59356 MeV}
11/2-
157m2Ta7315784Tantalum-157m2156.96823(16) u
[156.9281876 u]
{-29.59356 MeV}
(25/2-)
158Ta7315885Tantalum-158157.96654(21) u
[157.9264976 u]
{-31.16779 MeV}
(2-)162Re
158mTa7315885Tantalum-158m157.96654(21) u
[157.9264976 u]
{-31.16779 MeV}
(9+)
158m2Ta7315885Tantalum-158m2157.96654(21) u
[157.9264976 u]
{-31.16779 MeV}
(19-)
159Ta7315986Tantalum-159158.963028(21) u
[158.9229856 u]
{-34.4392 MeV}
1/2+163Re
159mTa7315986Tantalum-159m158.963028(21) u
[158.9229856 u]
{-34.4392 MeV}
11/2-
160Ta7316087Tantalum-160159.96154(6) u
[159.9214976 u]
{-35.82526 MeV}
164Re
160mTa7316087Tantalum-160m159.96154(6) u
[159.9214976 u]
{-35.82526 MeV}
161Ta7316188Tantalum-161160.958369(26) u
[160.9183266 u]
{-38.77903 MeV}
(1/2+)165Re
162Ta7316289Tantalum-162161.95729(6) u
[161.9172476 u]
{-39.78411 MeV}
166Re
163Ta7316390Tantalum-163162.95434(4) u
[162.9142976 u]
{-42.53202 MeV}
167Re
164Ta7316491Tantalum-164163.95353(3) u
[163.9134876 u]
{-43.28653 MeV}
(3+)168Re
164W
165Ta7316592Tantalum-165164.95078(15) u
[164.9107376 u]
{-45.84813 MeV}
(9/2-)169Re
165W
166Ta7316693Tantalum-166165.95051(3) u
[165.9104676 u]
{-46.09964 MeV}
(2)+166W
167Ta7316794Tantalum-167166.94809(3) u
[166.9080476 u]
{-48.35385 MeV}
(3/2+)167W
168Ta7316895Tantalum-168167.94805(3) u
[167.9080076 u]
{-48.39111 MeV}
(2-,3+)168W
169Ta7316996Tantalum-169168.94601(3) u
[168.9059676 u]
{-50.29136 MeV}
(5/2+)
170Ta7317097Tantalum-170169.94617(3) u
[169.9061276 u]
{-50.14232 MeV}
(3+)170W
171Ta7317198Tantalum-171170.94448(3) u
[170.9044376 u]
{-51.71655 MeV}
(5/2-)171W
172Ta7317299Tantalum-172171.94489(3) u
[171.9048476 u]
{-51.33463 MeV}
(3+)172W
173Ta73173100Tantalum-173172.94375(3) u
[172.9037076 u]
{-52.39654 MeV}
5/2-1.703(34)173W
174Ta73174101Tantalum-174173.94445(3) u
[173.9044076 u]
{-51.74449 MeV}
3+174W
175Ta73175102Tantalum-175174.94374(3) u
[174.9036976 u]
{-52.40585 MeV}
7/2+2.270(45)175W
176Ta73176103Tantalum-176175.94486(3) u
[175.9048176 u]
{-51.36258 MeV}
(1)-176W
177Ta73177104Tantalum-177176.944482(4) u
[176.9044396 u]
{-51.71468 MeV}
7/2+2.25(5)177W
178Ta73178105Tantalum-178177.94568(6) u
[177.9056376 u]
{-50.59875 MeV}
7-178W
179Ta73179106Tantalum-179178.9459392(16) u
[178.9058968 u]
{-50.35731 MeV}
7/2++ 2.289(9)179W
180Ta73180107Tantalum-180179.9474684(21) u
[179.907426 u]
{-48.93287 MeV}
1+180Hf
180mTa73180107Tantalum-180m179.9474684(21) u
[179.907426 u]
{-48.93287 MeV}
9-4.825(11)
181Ta73181108Tantalum-181180.94800(2) u
[180.9079576 u]
{-48.43769 MeV}
7/2++ 2.3705(7)181Hf
181W
182Ta73182109Tantalum-182181.9501554(15) u
[181.910113 u]
{-46.42995 MeV}
3-(+) 3.02(3)182Hf
182mTa73182109Tantalum-182m181.9501554(15) u
[181.910113 u]
{-46.42995 MeV}
5+
182m2Ta73182109Tantalum-182m2181.9501554(15) u
[181.910113 u]
{-46.42995 MeV}
10-
183Ta73183110Tantalum-183182.9513762(15) u
[182.9113338 u]
{-45.29278 MeV}
7/2++2.36(4)183Hf
184Ta73184111Tantalum-184183.954010(28) u
[183.9139676 u]
{-42.83941 MeV}
(5-)184Hf
185Ta73185112Tantalum-185184.955561(15) u
[184.9155186 u]
{-41.39466 MeV}
(7/2+)185Hf
186Ta73186113Tantalum-186185.95855(6) u
[185.9185076 u]
{-38.61043 MeV}
(2-,3-)186Hf
187Ta73187114Tantalum-187186.96039(6) u
[186.9203476 u]
{-36.89648 MeV}
188Ta73188115Tantalum-188187.96392(6) u
[187.9238776 u]
{-33.6083 MeV}
(1-)
189Ta73189116Tantalum-189188.96583(21) u
[188.9257876 u]
{-31.82915 MeV}
(7/2+)
190Ta73190117Tantalum-190189.96939(21) u
[189.9293476 u]
{-28.51303 MeV}
191Ta73191118Tantalum-191190.97156(32) u
[190.9315176 u]
{-26.49169 MeV}
192Ta73192119Tantalum-192191.97524(43) u
[191.9351976 u]
{-23.06379 MeV}
(1,2)
193Ta73193120Tantalum-193192.97759(43) u
[192.9375476 u]
{-20.87478 MeV}
194Ta73194121Tantalum-194193.98143(54) u
[193.9413876 u]
{-17.29784 MeV}

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
Ta-1552.9 msp → 154Hf100 %AL
Ta-156106(4) 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) %

102(7) keV
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 %22(5) keV
Ta-157m21.7(1) msα → 153Lu100 %1589(10) keV
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) %

141(9) keV
Ta-158m26.1(1) μsIso → 158Ta
α → 154Lu
98.6(2) %
1.4(2) %

2805.55(4) keV
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) %

64(5) keV
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?+x keV
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 a77.2(12) keV
Ta-181stableAL
Ta-182114.74(12) dβ-182W100 %1.8161(14) MeVAL
Ta-182m283(3) msIso → 182Ta100 %16.273(4) keV
Ta-182m215.84(10) minIso → 182Ta100 %519.577(16) keV
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 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Tantalum isotope.
6 - 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.
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 Tantalum 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 Tantalum 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)
180mTa
0,01201(32) %
9-
4,825(11)+ 495(2)
181Ta
99,98799(32) %
7/2+
+ 2,3705(7)3,2445+ 317,0(20)5,16270,03744
2,5464

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 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.

 


Category: Isotopes

Last update: 05.07.2020



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