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Isotopes of tantalum



Natural Tantalum (Ta) consists of two isotopes. Ta-181 is a stable isotope, and Ta-180m has a half life of over 1015 years (see scientific notation) and is a nuclear isomer of Ta-180. Ta-180 has a ground state half life of only 8 hours.

Tantalum has been proposed as a "salting" material for nuclear weapons (cobalt is another, better-known salting material). A jacket of 181Ta, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope 182Ta with a half-life of 114.43 days and produce approximately 1.12 MeV of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several months. Such a weapon is not known to have ever been built, tested, or used.


Standard atomic mass: 180.94788(2) u

Table

nuclide
symbol
Z(p) N(n)  
isotopic mass (u)
 
half-life nuclear
spin
representative
isotopic
composition
(mole fraction)
range of natural
variation
(mole fraction)
excitation energy
155Ta 73 82 154.97459(54)# 13(4) µs [12(+4-3) µs] (11/2-)
156Ta 73 83 155.97230(43)# 144(24) ms (2-)
156mTa 102(7) keV 0.36(4) s 9+
157Ta 73 84 156.96819(22) 10.1(4) ms 1/2+
157m1Ta 22(5) keV 4.3(1) ms 11/2-
157m2Ta 1593(9) keV 1.7(1) ms (25/2-)
158Ta 73 85 157.96670(22)# 49(8) ms (2-)
158mTa 141(9) keV 36.0(8) ms (9+)
159Ta 73 86 158.963018(22) 1.04(9) s (1/2+)
159mTa 64(5) keV 514(9) ms (11/2-)
160Ta 73 87 159.96149(10) 1.70(20) s (2#)-
160mTa 310(90)# keV 1.55(4) s (9)+
161Ta 73 88 160.95842(6)# 3# s 1/2+#
161mTa 50(50)# keV 2.89(12) s 11/2-#
162Ta 73 89 161.95729(6) 3.57(12) s 3+#
163Ta 73 90 162.95433(4) 10.6(18) s 1/2+#
164Ta 73 91 163.95353(3) 14.2(3) s (3+)
165Ta 73 92 164.950773(19) 31.0(15) s 5/2-#
165mTa 60(30) keV 9/2-#
166Ta 73 93 165.95051(3) 34.4(5) s (2)+
167Ta 73 94 166.94809(3) 1.33(7) min (3/2+)
168Ta 73 95 167.94805(3) 2.0(1) min (2-,3+)
169Ta 73 96 168.94601(3) 4.9(4) min (5/2+)
170Ta 73 97 169.94618(3) 6.76(6) min (3)(+#)
171Ta 73 98 170.94448(3) 23.3(3) min (5/2-)
172Ta 73 99 171.94490(3) 36.8(3) min (3+)
173Ta 73 100 172.94375(3) 3.14(13) h 5/2-
174Ta 73 101 173.94445(3) 1.14(8) h 3+
175Ta 73 102 174.94374(3) 10.5(2) h 7/2+
176Ta 73 103 175.94486(3) 8.09(5) h (1)-
176m1Ta 103.0(10) keV 1.1(1) ms (+)
176m2Ta 1372.6(11)+X keV 3.8(4) µs (14-)
176m3Ta 2820(50) keV 0.97(7) ms (20-)
177Ta 73 104 176.944472(4) 56.56(6) h 7/2+
177m1Ta 73.36(15) keV 410(7) ns 9/2-
177m2Ta 186.15(6) keV 3.62(10) µs 5/2-
177m3Ta 1355.01(19) keV 5.31(25) µs 21/2-
177m4Ta 4656.3(5) keV 133(4) µs 49/2-
178Ta 73 105 177.945778(16) 9.31(3) min 1+
178m1Ta 100(50)# keV 2.36(8) h (7)-
178m2Ta 1570(50)# keV 59(3) ms (15-)
178m3Ta 3000(50)# keV 290(12) ms (21-)
179Ta 73 106 178.9459295(23) 1.82(3) a 7/2+
179m1Ta 30.7(1) keV 1.42(8) µs (9/2)-
179m2Ta 520.23(18) keV 335(45) ns (1/2)+
179m3Ta 1252.61(23) keV 322(16) ns (21/2-)
179m4Ta 1317.3(4) keV 9.0(2) ms (25/2+)
179m5Ta 1327.9(4) keV 1.6(4) µs (23/2-)
179m6Ta 2639.3(5) keV 54.1(17) ms (37/2+)
180Ta 73 107 179.9474648(24) 8.152(6) h 1+
180m1Ta 77.1(8) keV >1.2E+15 a 9- 0.00012(2)
180m2Ta 1452.40(18) keV 31.2(14) µs 15-
180m3Ta 3679.0(11) keV 2.0(5) µs (22-)
180m4Ta 4171.0+X keV 17(5) µs (23,24,25)
181Ta 73 108 180.9479958(19) STABLE 7/2+ 0.99988(2)
181m1Ta 6.238(20) keV 6.05(12) µs 9/2-
181m2Ta 615.21(3) keV 18(1) µs 1/2+
181m3Ta 1485(3) keV 25(2) µs 21/2-
181m4Ta 2230(3) keV 210(20) µs 29/2-
182Ta 73 109 181.9501518(19) 114.43(3) d 3-
182m1Ta 16.263(3) keV 283(3) ms 5+
182m2Ta 519.572(18) keV 15.84(10) min 10-
183Ta 73 110 182.9513726(19) 5.1(1) d 7/2+
183mTa 73.174(12) keV 107(11) ns 9/2-
184Ta 73 111 183.954008(28) 8.7(1) h (5-)
185Ta 73 112 184.955559(15) 49.4(15) min (7/2+)#
185mTa 1308(29) keV >1 ms (21/2-)
186Ta 73 113 185.95855(6) 10.5(3) min (2-,3-)
186mTa 1.54(5) min
187Ta 73 114 186.96053(21)# 2# min [>300 ns] 7/2+#
188Ta 73 115 187.96370(21)# 20# s [>300 ns]
189Ta 73 116 188.96583(32)# 3# s [>300 ns] 7/2+#
190Ta 73 117 189.96923(43)# 0.3# s

Notes

  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

  • Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
  • Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
  • Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
    • Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
    • National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
    • David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.


Isotopes of hafnium Isotopes of tantalum Isotopes of tungsten
Index to isotope pages
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Isotopes_of_tantalum". A list of authors is available in Wikipedia.
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