Bismuth-209

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Template:Short description Script error: No such module "Infobox".Template:Template otherScript error: No such module "Check for unknown parameters". Bismuth-209 (209Bi) is an isotope of bismuth, with the longest known half-life of any radioisotope that undergoes α-decay (alpha decay). It has 83 protons and a magic number[1] of 126 neutrons,[1] and an atomic mass of Template:Val. Primordial bismuth consists entirely of this isotope.

Decay properties

Bismuth-209 was long thought to have the heaviest stable nucleus of any element, but in 2003, a research team at the Institut d'Astrophysique Spatiale in Orsay, France, discovered that 209Bi undergoes alpha decay with a half-life of 20.1 exayears (Template:Val, or 20.1 quintillion years),[2][3] over 109 times longer than the estimated age of the universe.[4] The heaviest nucleus considered to be stable is now lead-208 and the heaviest stable monoisotopic element is gold (gold-197).

Theory had previously predicted a half-life of 4.6Template:E years. It had been suspected to be radioactive for a long time.[5] The decay produces a 3.14 MeV alpha particle plus thallium-205.[2][3]

File:Decay Chain(4n+1, Neptunium Series).svg
Bismuth-209 occurs in the neptunium series decay chain.

Bismuth-209 forms 205Tl:

Template:Nuclide → Template:Nuclide + Template:Nuclide[6]

If perturbed, it would join in lead-bismuth neutron capture cycle from lead-206/207/208 to bismuth-209, despite low capture cross sections. Even thallium-205, the decay product of bismuth-209, reverts to lead when fully ionized.[7]

Due to its extremely long half-life, 209Bi can be treated as non-radioactive for nearly all applications. It is much less radioactive than human flesh, so it poses no real radiation hazard. Though 209Bi holds the half-life record for alpha decay, it does not have the longest known half-life of any nuclide; this distinction belongs to tellurium-128 (128Te) with a half-life estimated at Template:Val years by double β-decay (double beta decay).[8][9][10]

The half-life of 209Bi was confirmed in 2012 by an Italian team in Gran Sasso who reported Template:Val years. They also reported an even longer half-life for alpha decay of 209Bi to the first excited state of 205Tl (at 204 keV), was estimated at 1.66Template:E years.[11] Even though this value is shorter than the half-life of 128Te, both alpha decays of 209Bi hold the record of the thinnest natural line widths of any measurable physical excitation, estimated respectively at ΔΕ ≈ Template:Val and ΔΕ ≈ Template:Val in application of the uncertainty principle[12] (double beta decay would produce energy lines only in neutrinoless transitions, which has not been observed yet).

Applications

Because all primordial bismuth is bismuth-209, bismuth-209 is used for all normal applications of bismuth, such as being used as a replacement for lead,[13][14] in cosmetics,[15][16] in paints,[17] and in several medicines such as Pepto-Bismol.[4][18][19] Alloys containing bismuth-209 such as bismuth bronze have been used for thousands of years.[20]

Synthesis of other elements

210Po can be manufactured by bombarding 209Bi with neutrons in a nuclear reactor.[21] Only around 100 grams of 210Po are produced each year.[22][21] 209Po and 208Po can be made through the proton bombardment of 209Bi in a cyclotron.[23] Astatine can also be produced by bombarding 209Bi with alpha particles.[24][25][26] Traces of 209Bi have also been used to create gold in nuclear reactors.[27][28]

209Bi has been used as a target for the creation of several isotopes of superheavy elements such as dubnium,[29][30][31][32] bohrium,[29][33] meitnerium,[34][35][36] roentgenium,[37][38][39] and nihonium.[40][41][42]

Formation

Primordial

File:S-R-processes-atomic-mass-201-to-210.svg
Bismuth-209 is created in the final part of the s-process.Template:Efn

In the red giant stars of the asymptotic giant branch, the s-process (slow process) is ongoing to produce bismuth-209 and polonium-210 by neutron capture as the heaviest elements to be formed,[43] and the latter quickly decays.[43] All elements heavier than it are formed in the r-process, or rapid process, which occurs during the first fifteen minutes of supernovas.[44][43] Bismuth-209 is also created during the r-process.[43]

Radiogenic

Some 209Bi was created radiogenically from the neptunium decay chain.[45] Neptunium-237 is an extinct radionuclide, but it can be found in traces in uranium ores because of neutron capture reactions.[45][46] Americium-241, which is used in smoke detectors,[47] decays to neptunium-237.

See also

Notes

Template:Notelist

Lighter:
bismuth-208 		Bismuth-209 is an
isotope of bismuth 		Heavier:
bismuth-210
Decay product of:
astatine-213 (α)
polonium-209 (β+)
lead-209 (β−) 		Decay chain
of bismuth-209 		Decays to:
thallium-205 (α)

Template:S-endScript error: No such module "Check for unknown parameters".

References

Template:Reflist

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  1. ↑ a b Script error: No such module "Citation/CS1".
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  5. ↑ Script error: No such module "Citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ Script error: No such module "citation/CS1". Tellurium-128 information and half-life. Accessed July 14, 2009.
  9. ↑ Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ Script error: No such module "Citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "Citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ B. Gunter "Inorganic Colored Pigments” in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2012.
  18. ↑ Script error: No such module "Citation/CS1".
  19. ↑ Merck Index, 11th Edition, 1299
  20. ↑ Script error: No such module "Citation/CS1".
  21. ↑ a b Template:Cite magazine
  22. ↑ Script error: No such module "citation/CS1".
  23. ↑ Script error: No such module "citation/CS1".
  24. ↑ Script error: No such module "Citation/CS1". Template:Subscription required
  25. ↑ Script error: No such module "Citation/CS1".
  26. ↑ Script error: No such module "Citation/CS1". Template:Subscription required
  27. ↑ Script error: No such module "Citation/CS1".
  28. ↑ Script error: No such module "citation/CS1".
  29. ↑ a b Script error: No such module "Citation/CS1".
  30. ↑ Script error: No such module "Citation/CS1".
  31. ↑ Script error: No such module "Citation/CS1".
  32. ↑ Template:Cite thesis
  33. ↑ Script error: No such module "Citation/CS1".
  34. ↑ Script error: No such module "Citation/CS1".
  35. ↑ Script error: No such module "Citation/CS1".
  36. ↑ Script error: No such module "Citation/CS1".
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  38. ↑ Script error: No such module "Citation/CS1".
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  40. ↑ Script error: No such module "Citation/CS1".
  41. ↑ Script error: No such module "Citation/CS1".
  42. ↑ Script error: No such module "Citation/CS1".
  43. ↑ a b c d Script error: No such module "Citation/CS1".
  44. ↑ Chaisson, Eric, and Steve McMillan. Astronomy Today. 6th ed. San Francisco: Pearson Education, 2008.
  45. ↑ a b Script error: No such module "Citation/CS1".
  46. ↑ Script error: No such module "citation/CS1".
  47. ↑ Script error: No such module "Citation/CS1".
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