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Isotopes of tungsten

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Isotopes of tungsten (74W)
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
180W 0.120% 1.8×1018 y α 176Hf
181W synth 121.2 d ε 181Ta
182W 26.5% stable
183W 14.3% stable
184W 30.6% stable
185W synth 75.1 d β 185Re
186W 28.4% stable
188W synth 69.78 d β 188Re
Standard atomic weight Ar°(W)

Naturally occurring tungsten (74W) consists of five isotopes. Four are considered stable (182W, 183W, 184W, and 186W) and one is slightly radioactive, 180W, with an extremely long half-life of 1.8 ± 0.2 exayears (1018 years). On average, two alpha decays of 180W occur per gram of natural tungsten per year, so for most practical purposes, 180W can be considered stable. Theoretically, all five can decay into isotopes of element 72 (hafnium) by alpha emission, but only 180W has been observed to do so. The other naturally occurring isotopes have not been observed to decay (they are observationally stable), and lower bounds for their half-lives have been established:

182W, t1/2 > 7.7×1021 years
183W, t1/2 > 4.1×1021 years
184W, t1/2 > 8.9×1021 years
186W, t1/2 > 8.2×1021 years

Thirty-four artificial radioisotopes of tungsten have been characterized with mass numbers ranging from 156 to 194, 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 11 meta states with mass numbers of 158, 179, with 3, 180, with 2, 183, 185, 186, with 2, and 190, the most stable being 179m1W (t1/2 6.4 minutes).

List of isotopes

[edit]


Nuclide
[n 1]
Z N Isotopic mass (Da)
[n 2][n 3]
Half-life
[n 4][n 5]
Decay
mode

[n 6]
Daughter
isotope

[n 7][n 8]
Spin and
parity
[n 9][n 5]
Natural abundance (mole fraction)
Excitation energy Normal proportion Range of variation
156W[3] 74 82 157+57
−34
 ms
β+ 156Ta 0+
157W[4] 74 83 275(40) ms β+ 157Ta (7/2−)
158W 74 84 157.97456(54)# 1.37(17) ms α 154Hf 0+
158mW 1889(8) keV 143(19) μs α 154Hf 8+
159W 74 85 158.97292(43)# 8.2(7) ms α (82%) 155Hf 7/2−#
β+ (18%) 159Ta
160W 74 86 159.96848(22) 90(5) ms α (87%) 156Hf 0+
β+ (14%) 160Ta
161W 74 87 160.96736(21)# 409(16) ms α (73%) 157Hf 7/2−#
β+ (23%) 161Ta
162W 74 88 161.963497(19) 1.36(7) s β+ (53%) 162Ta 0+
α (47%) 158Hf
163W 74 89 162.96252(6) 2.8(2) s β+ (59%) 163Ta 3/2−#
α (41%) 159Hf
164W 74 90 163.958954(13) 6.3(2) s β+ (97.4%) 164Ta 0+
α (2.6%) 160Hf
165W 74 91 164.958280(27) 5.1(5) s β+ (99.8%) 165Ta 3/2−#
α (.2%) 161Hf
166W 74 92 165.955027(11) 19.2(6) s β+ (99.96%) 166Ta 0+
α (.035%) 162Hf
167W 74 93 166.954816(21) 19.9(5) s β+ (>99.9%) 167Ta 3/2−#
α (<.1%) 163Hf
168W 74 94 167.951808(17) 51(2) s β+ (99.99%) 168Ta 0+
α (.0319%) 164Hf
169W 74 95 168.951779(17) 76(6) s β+ 169Ta (5/2−)
170W 74 96 169.949228(16) 2.42(4) min β+(99%) 170Ta 0+
α (1%) 166Hf
171W 74 97 170.94945(3) 2.38(4) min β+ 171Ta (5/2−)
172W 74 98 171.94729(3) 6.6(9) min β+ 172Ta 0+
173W 74 99 172.94769(3) 7.6(2) min β+ 173Ta 5/2−
174W 74 100 173.94608(3) 33.2(21) min β+ 174Ta 0+
175W 74 101 174.94672(3) 35.2(6) min β+ 175Ta (1/2−)
176W 74 102 175.94563(3) 2.5(1) h EC 176Ta 0+
177W 74 103 176.94664(3) 132(2) min β+ 177Ta 1/2−
178W 74 104 177.945876(16) 21.6(3) d EC 178Ta 0+
179W 74 105 178.947070(17) 37.05(16) min β+ 179Ta (7/2)−
179m1W 221.926(8) keV 6.40(7) min IT (99.72%) 179W (1/2)−
β+ (.28%) 179Ta
179m2W 1631.90(8) keV 390(30) ns (21/2+)
179m3W 3348.45(16) keV 750(80) ns (35/2−)
180W[n 10] 74 106 179.946704(4) 1.8(0.2)×1018 y α 176Hf 0+ 0.0012(1)
180m1W 1529.04(3) keV 5.47(9) ms IT 180W 8−
180m2W 3264.56(21) keV 2.33(19) μs 14−
181W 74 107 180.948197(5) 121.2(2) d EC 181Ta 9/2+
182W 74 108 181.9482042(9) Observationally Stable[n 11] 0+ 0.2650(16)
183W 74 109 182.9502230(9) Observationally Stable[n 12] 1/2− 0.1431(4)
183mW 309.493(3) keV 5.2(3) s IT 183W 11/2+
184W 74 110 183.9509312(9) Observationally Stable[n 13] 0+ 0.3064(2)
185W 74 111 184.9534193(10) 75.1(3) d β 185Re 3/2−
185mW 197.43(5) keV 1.597(4) min IT 185W 11/2+
186W 74 112 185.9543641(19) Observationally Stable[n 14] 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 β 187Re 3/2−
188W 74 114 187.958489(4) 69.78(5) d β 188Re 0+
189W 74 115 188.96191(21) 11.6(3) min β 189Re (3/2−)
190W 74 116 189.96318(18) 30.0(15) min β 190Re 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+
This table header & footer:
  1. ^ mW – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. ^ Bold half-life – nearly stable, half-life longer than age of universe.
  5. ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ^ Modes of decay:
    EC: Electron capture
    IT: Isomeric transition
  7. ^ Bold italics symbol as daughter – Daughter product is nearly stable.
  8. ^ Bold symbol as daughter – Daughter product is stable.
  9. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  10. ^ Primordial radionuclide
  11. ^ Believed to undergo α decay to 178Hf with a half-life over 7.7×1021 y
  12. ^ Believed to undergo α decay to 179Hf with a half-life over 4.1×1021 y
  13. ^ Believed to undergo α decay to 180Hf with a half-life over 8.9×1021 y
  14. ^ Believed to undergo α decay to 182Hf or ββ decay to 186Os with a half-life over 8.2×1021 y

References

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  1. ^ "Standard Atomic Weights: Tungsten". CIAAW. 1991.
  2. ^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
  3. ^ Briscoe, A. D.; Page, R. D.; Uusitalo, J.; et al. (2023). "Decay spectroscopy at the two-proton drip line: Radioactivity of the new nuclides 160Os and 156W". Physics Letters B. 47 (138310). doi:10.1016/j.physletb.2023.138310. hdl:10272/23933.
  4. ^ Bianco, L.; Page, R. D.; Darby, I. G.; et al. (7 June 2010). "Discovery of 157W and 161Os" (PDF). Physics Letters B. 690 (1): 15–18. Bibcode:2010PhLB..690...15B. doi:10.1016/j.physletb.2010.04.056. ISSN 0370-2693. S2CID 117121162. Retrieved 11 June 2023.