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List of isotopes

Lead-206

See also: Decay chain

206Pb is the final step in the decay chain of 238U, the "radium series" or "uranium series". In a closed system, over time, a given mass of 238U will decay in a sequence of steps culminating in 206Pb. The production of intermediate products eventually reaches an equilibrium (though this takes a long time, as the half-life of 234U is 245,500 years). Once this stabilized system is reached, the ratio of 238U to 206Pb will steadily decrease, while the ratios of the other intermediate products to each other remain constant.

Like most radioisotopes found in the radium series, 206Pb was initially named as a variation of radium, specifically radium G. It is the decay product of both 210Po (historically called radium F) by alpha decay, and the much rarer 206Tl (radium EII) by beta decay.

Lead-206 has been proposed for use in fast breeder nuclear fission reactor coolant over the use of natural lead mixture (which also includes other stable lead isotopes) as a mechanism to improve neutron economy and greatly suppress unwanted production of highly radioactive byproducts.⁴¹

Lead-204, -207, and -208

204Pb is entirely primordial, and is thus useful for estimating the fraction of the other lead isotopes in a given sample that are also primordial, since the relative fractions of the various primordial lead isotopes is constant everywhere.⁴² Any excess lead-206, -207, and -208 is thus assumed to be radiogenic in origin,⁴³ allowing various uranium and thorium dating schemes to be used to estimate the age of rocks (time since their formation) based on the relative abundance of lead-204 to other isotopes. 207Pb is the end of the actinium series from 235U.

208Pb is the end of the thorium series from 232Th. While it only makes up approximately half of the composition of lead in most places on Earth, it can be found naturally enriched up to around 90% in thorium ores.⁴⁴ 208Pb is the heaviest known stable nuclide and also the heaviest known doubly magic nucleus, as Z = 82 and N = 126 correspond to closed nuclear shells.⁴⁵ As a consequence of this particularly stable configuration, its neutron capture cross section is very low (even lower than that of deuterium in the thermal spectrum), making it of interest for lead-cooled fast reactors.

In 2025 a published study suggested that the nucleus of 208Pb is not perfectly spherical as previously believed.⁴⁶

Lead-212

212Pb-containing radiopharmaceuticals have been trialed as therapeutic agents for the experimental cancer treatment targeted alpha-particle therapy.⁴⁷

Sources

• Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–291. doi:10.1515/pac-2015-0305.

Isotope masses from:

• Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001

Half-life, spin, and isomer data selected from the following sources.

• Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
• National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
• Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.

References

1. Jeter, Hewitt W. (March 2000). "Determining the Ages of Recent Sediments Using Measurements of Trace Radioactivity" (PDF). Terra et Aqua (78): 21–28. Archived from the original (PDF) on March 4, 2016. Retrieved October 23, 2019. https://web.archive.org/web/20160304043824/https://www.iadc-dredging.com/ul/cms/terraetaqua/document/0/9/0/90/90/1/terra-et-aqua-nr78-03.pdf ↩

2. Blank, B.; Regan, P.H. (2000). "Magic and doubly-magic nuclei". Nuclear Physics News. 10 (4): 20–27. doi:10.1080/10506890109411553. S2CID 121966707. https://www.researchgate.net/publication/232899048 ↩

3. Takahashi, K; Boyd, R. N.; Mathews, G. J.; Yokoi, K. (October 1987). "Bound-state beta decay of highly ionized atoms". Physical Review C. 36 (4): 1522–1528. Bibcode:1987PhRvC..36.1522T. doi:10.1103/PhysRevC.36.1522. ISSN 0556-2813. OCLC 1639677. PMID 9954244. Retrieved 2016-11-20. As can be seen in Table I (187Re, 210Pb, 227Ac, and 241Pu), some continuum-state decays are energetically forbidden when the atom is fully ionized. This is because the atomic binding energies liberated by ionization, i.e., the total electron binding in the neutral atom, Bn, increases with Z. If [the decay energy] Qnhttps://www.researchgate.net/publication/13335547 ↩

4. mPb – Excited nuclear isomer. /wiki/Nuclear_isomer ↩

5. Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf. /wiki/Doi_(identifier) ↩

6. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits. ↩

7. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS). ↩

8. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf ↩

9. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf ↩

10. Modes of decay: EC:Electron captureIT:Isomeric transition /wiki/Electron_capture ↩

11. Bold italics symbol as daughter – Daughter product is nearly stable. ↩

12. Bold symbol as daughter – Daughter product is stable. ↩

13. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf ↩

14. ( ) spin value – Indicates spin with weak assignment arguments. ↩

15. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN). ↩

16. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN). ↩

17. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae. https://www-nds.iaea.org/amdc/ame2020/NUBASE2020.pdf ↩

18. Order of ground state and isomer is uncertain. ↩

19. Order of ground state and isomer is uncertain. ↩

20. Used in lead–lead dating /wiki/Lead%E2%80%93lead_dating ↩

21. Believed to undergo α decay to 200Hg with a half-life over 1.4×1020 years; the theoretical lifetime is around ~1035–37 years.[9] /wiki/Half-life ↩

22. "Standard Atomic Weights: Lead". CIAAW. 2020. https://www.ciaaw.org/lead.htm ↩

23. Used in lead–lead dating /wiki/Lead%E2%80%93lead_dating ↩

24. Final decay product of 4n+2 decay chain (the Radium or Uranium series) /wiki/Decay_product ↩

25. Kuhn, W. (1929). "LXVIII. Scattering of thorium C" γ-radiation by radium G and ordinary lead". The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science. 8 (52): 628. doi:10.1080/14786441108564923. /wiki/Doi_(identifier) ↩

26. Believed to undergo α decay to 202Hg with a half-life over 2.5×1021 years; the theoretical lifetime is ~1065–68 years.[9] ↩

27. "Standard Atomic Weights: Lead". CIAAW. 2020. https://www.ciaaw.org/lead.htm ↩

28. Used in lead–lead dating /wiki/Lead%E2%80%93lead_dating ↩

29. Final decay product of 4n+3 decay chain (the Actinium series) /wiki/Actinium_series ↩

30. Believed to undergo α decay to 203Hg with a half-life over 1.9×1021 years; the theoretical lifetime is ~10152–189 years.[9] ↩

31. "Standard Atomic Weights: Lead". CIAAW. 2020. https://www.ciaaw.org/lead.htm ↩

32. Heaviest observationally stable nuclide; final decay product of 4n decay chain (the Thorium series) /wiki/Thorium_series ↩

33. Believed to undergo α decay to 204Hg with a half-life over 2.6×1021 years; the theoretical lifetime is ~10124–132 years.[9] ↩

34. "Standard Atomic Weights: Lead". CIAAW. 2020. https://www.ciaaw.org/lead.htm ↩

35. Intermediate decay product of 237Np /wiki/Neptunium-237 ↩

36. Intermediate decay product of 238U /wiki/Decay_product ↩

37. Intermediate decay product of 235U /wiki/Decay_product ↩

38. Intermediate decay product of 232Th /wiki/Decay_product ↩

39. Intermediate decay product of 237Np /wiki/Neptunium-237 ↩

40. Intermediate decay product of 238U /wiki/Decay_product ↩

41. Khorasanov, G. L.; Ivanov, A. P.; Blokhin, A. I. (2002). Polonium Issue in Fast Reactor Lead Coolants and One of the Ways of Its Solution. 10th International Conference on Nuclear Engineering. pp. 711–717. doi:10.1115/ICONE10-22330. https://www.researchgate.net/publication/255203791 ↩

42. Woods, G.D. (November 2014). Lead isotope analysis: Removal of 204Hg isobaric interference from 204Pb using ICP-QQQ in MS/MS mode (PDF) (Report). Stockport, UK: Agilent Technologies. https://www.agilent.com/cs/library/applications/5991-5270EN_AppNote8800_ICP-QQQ_Pb.pdf ↩

43. Woods, G.D. (November 2014). Lead isotope analysis: Removal of 204Hg isobaric interference from 204Pb using ICP-QQQ in MS/MS mode (PDF) (Report). Stockport, UK: Agilent Technologies. https://www.agilent.com/cs/library/applications/5991-5270EN_AppNote8800_ICP-QQQ_Pb.pdf ↩

44. A. Yu. Smirnov; V. D. Borisevich; A. Sulaberidze (July 2012). "Evaluation of specific cost of obtainment of lead-208 isotope by gas centrifuges using various raw materials". Theoretical Foundations of Chemical Engineering. 46 (4): 373–378. doi:10.1134/S0040579512040161. S2CID 98821122. /wiki/Doi_(identifier) ↩

45. Blank, B.; Regan, P.H. (2000). "Magic and doubly-magic nuclei". Nuclear Physics News. 10 (4): 20–27. doi:10.1080/10506890109411553. S2CID 121966707. https://www.researchgate.net/publication/232899048 ↩

46. Henderson, J.; Heery, J.; Rocchini, M.; Siciliano, M.; Sensharma, N.; Ayangeakaa, A. D.; Janssens, R. V. F.; Kowalewski, T. M.; Abhishek; Stevenson, P. D.; Yüksel, E.; Brown, B. A.; Rodriguez, T. R.; Robledo, L. M.; Wu, C. Y. (2025-02-14). "Deformation and Collectivity in Doubly Magic Pb208". Physical Review Letters. 134 (6): 062502. doi:10.1103/PhysRevLett.134.062502. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.062502 ↩

47. Kokov, K.V.; Egorova, B.V.; German, M.N.; Klabukov, I.D.; Krasheninnikov, M.E.; Larkin-Kondrov, A.A.; Makoveeva, K.A.; Ovchinnikov, M.V.; Sidorova, M.V.; Chuvilin, D.Y. (2022). "212Pb: Production Approaches and Targeted Therapy Applications". Pharmaceutics. 14 (1): 189. doi:10.3390/pharmaceutics14010189. ISSN 1999-4923. PMC 8777968. PMID 35057083. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8777968 ↩