There are two naturalisotopes ofiridium (₇₇Ir), and 37radioisotopes, the most stable radioisotope being¹⁹²Ir with ahalf-life of 73.83 days, and manynuclear isomers, the most stable of which is^192m2Ir with a half-life of 241 years. All other isomers have half-lives under a year, most under a day. All isotopes of iridium are either radioactive orobservationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed.^[4]

Iridium-192 (symbol¹⁹²Ir) is a radioactiveisotope ofiridium, with ahalf-life of 73.83 days.^[11] It decays by emitting beta (β) particles and gamma (γ) radiation. About 96% of¹⁹²Ir decays occur via emission of β and γ radiation, leading to¹⁹²Pt. Some of the β particles are captured by other¹⁹²Ir nuclei, which are then converted to¹⁹²Os. Electron capture is responsible for the remaining 4% of¹⁹²Ir decays.^[12] Iridium-192 is normally produced by neutron activation of natural-abundance iridium metal.^[13]

Iridium-192 is a very stronggamma ray emitter, with a gamma dose-constant of approximately 1.54μSv·h⁻¹·MBq⁻¹ at 30 cm, and a specific activity of 341TBq·g⁻¹ (9.22kCi·g⁻¹).^[14][15] There are seven principal energy packets produced during its disintegration process ranging from just over 0.2 to about 0.6 MeV.

The^192m2Ir isomer is unusual, both for its long half-life for an isomer, and that said half-life greatly exceeds that of the ground state of the same isotope.

• 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
• Isotopic compositions and standard atomic masses from:
  • de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003)."Atomic weights of the elements. Review 2000 (IUPAC Technical Report)".Pure and Applied Chemistry.75 (6):683–800.doi:10.1351/pac200375060683.
  • Wieser, Michael E. (2006)."Atomic weights of the elements 2005 (IUPAC Technical Report)".Pure and Applied Chemistry.78 (11):2051–2066.doi:10.1351/pac200678112051.
• "News & Notices: Standard Atomic Weights Revised".International Union of Pure and Applied Chemistry. 19 October 2005.
• 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.

• NLM Hazardous Substances Databank – Iridium, Radioactive (referring to iridium-192)

• Isotopes of iridium
• Iridium
• Lists of isotopes by element

• Articles with short description
• Short description is different from Wikidata