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Isotopes of tungsten



Naturally occurring Tungsten (W) consists of five isotopes whose half-lives are so long that they can be considered stable. All can decay into isotopes of element 72 (hafnium) by alpha emission; 180W has been observed to have a half life of 1.8 +- 0.2 Ea. The other naturally occurring isotopes have not been observed to decay, constraining their half-lives to be: 182W, T1/2 > 8.3 Ea; 184W, T1/2 > 29 Ea; 185W, T1/2 > 13 Ea; 186W, T1/2 > 27 Ea. [1] On average, two alpha decays of 180W occur in one gram of natural tungsten per year.

Additional recommended knowledge

27 artificial radioisotopes of tungsten have been characterized, the most stable of which are 181W with a half-life of 121.2 days, 185W with a half-life of 75.1 days, 188W with a half-life of 69.4 days and 178W with a half-life of 21.6 days. All of the remaining radioactive isotopes have half-lives of less than 24 hours, and most of these have half-lives that are less than 8 minutes. Tungsten also has 4 meta states, the most stable being 179mW (t½ 6.4 minutes).


Standard atomic mass: 183.84(1) 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
158W 74 84 157.97456(54)# 1.37(17) ms 0+
158mW 1889(8) keV 143(19) µs 8+
159W 74 85 158.97292(43)# 8.2(7) ms 7/2-#
160W 74 86 159.96848(22) 90(5) ms 0+
161W 74 87 160.96736(21)# 409(16) ms 7/2-#
162W 74 88 161.963497(19) 1.36(7) s 0+
163W 74 89 162.96252(6) 2.8(2) s 3/2-#
164W 74 90 163.958954(13) 6.3(2) s 0+
165W 74 91 164.958280(27) 5.1(5) s 3/2-#
166W 74 92 165.955027(11) 19.2(6) s 0+
167W 74 93 166.954816(21) 19.9(5) s 3/2-#
168W 74 94 167.951808(17) 51(2) s 0+
169W 74 95 168.951779(17) 76(6) s (5/2-)
170W 74 96 169.949228(16) 2.42(4) min 0+
171W 74 97 170.94945(3) 2.38(4) min (5/2-)
172W 74 98 171.94729(3) 6.6(9) min 0+
173W 74 99 172.94769(3) 7.6(2) min 5/2-
174W 74 100 173.94608(3) 33.2(21) min 0+
175W 74 101 174.94672(3) 35.2(6) min (1/2-)
176W 74 102 175.94563(3) 2.5(1) h 0+
177W 74 103 176.94664(3) 132(2) min 1/2-
178W 74 104 177.945876(16) 21.6(3) d 0+
179W 74 105 178.947070(17) 37.05(16) min (7/2)-
179m1W 221.926(8) keV 6.40(7) min (1/2)-
179m2W 1631.90(8) keV 390(30) ns (21/2+)
179m3W 3348.45(16) keV 750(80) ns (35/2-)
180W 74 106 179.946704(4) STABLE [>700E+15 a] 0+ 0.0012(1)
180m1W 1529.04(3) keV 5.47(9) ms 8-
180m2W 3264.56(21) keV 2.33(19) µs 14-
181W 74 107 180.948197(5) 121.2(2) d 9/2+
182W 74 108 181.9482042(9) STABLE [>170E+18 a] 0+ 0.2650(16)
183W 74 109 182.9502230(9) STABLE [>80E+18 a] 1/2- 0.1431(4)
183mW 309.493(3) keV 5.2(3) s 11/2+
184W 74 110 183.9509312(9) STABLE [>180E+18 a] 0+ 0.3064(2)
185W 74 111 184.9534193(10) 75.1(3) d 3/2-
185mW 197.43(5) keV 1.597(4) min 11/2+
186W 74 112 185.9543641(19) STABLE [>4.1E+18 a] 0+ 0.2843(19)
186m1W 1517.2(6) keV 18(1) µs (7-)
186m2W 3542.8(21) keV >3 ms (16+)
187W 74 113 186.9571605(19) 23.72(6) h 3/2-
188W 74 114 187.958489(4) 69.78(5) d 0+
189W 74 115 188.96191(21) 11.6(3) min (3/2-)
190W 74 116 189.96318(18) 30.0(15) min 0+
190mW 2381(5) keV <3.1 ms (10-)
191W 74 117 190.96660(21)# 20# s [>300 ns] 3/2-#
192W 74 118 191.96817(64)# 10# s [>300 ns] 0+

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