Isotopes of thallium

Thallium (Tl) has 25 isotopes which have atomic masses that range from 184 to 210. ²⁰³Tl and ²⁰⁵Tl are the only stable isotopes and ²⁰⁴Tl is the most stable radioisotope with a half-life of 3.78 years.

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Thallium-202 (half life 12.23 days) can be made in a cyclotron^[1] while thallium-204 (half life 3.78 years) is made by the neutron activation of stable thallium in a nuclear reactor.^[2]

Standard atomic mass: 204.3833(2) u

Isotopes of thallium occurring within the radioactive disintegration chains of actinium, radium and thorium were known as:

• radium E^II : ²⁰⁶Tl
• actinium C^II : ²⁰⁷Tl
• thorium C^II : ²⁰⁸Tl
• radium C^II : ²¹⁰Tl

Table

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.