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Isotopes of iridium
Iridium has two isotopes, Ir-191 and Ir-193 and both are used in the production of radioactive material. Ir-191 is used for the production of radioactive Ir-192. This Ir-192 is used as a radiation source in gamma cameras that are used for non-destructive testing. Ir-192 sources are also used in so-called brachytherapy procedures whereby radioactive materials are placed in close contact with the tissue being treated. Although Ir-192 can be produced from natural Ir, the use of enriched Ir-191 gives a much higher specific activity and allows the use of smaller sources. The use of Ir-193 has been suggested for the production of the therapeutic radioisotope Pt-195m. Iridium isotopes can be obtained from Trace Sciences International.
Naturally occurring isotopes
This table shows information about naturally occuring isotopes, their atomic masses, their natural abundances, their nuclear spins, and their magnetic moments. Further data for radioisotopes (radioactive isotopes) of iridium are listed (including any which occur naturally) below.
| Isotope |
Atomic mass (ma/u) |
Natural abundance (atom %) |
Nuclear spin (I) |
Magnetic moment (μ/μN) |
| 191Ir |
190.960584 (4) |
37.3 (2) |
3/2 |
0.1462 |
| 193Ir |
192.962917 (4) |
62.7 (2) |
3/2 |
0.1592 |
 In the above picture, the most intense ion is set to 100% since this corresponds best to the output from a mass spectrometer. This is not to be confused with the relative percentage isotope abundances which total 100% for all the naturally occurring isotopes.
Radiosotope data
Further data for naturally occuring isotopes of iridium are listed above. This table gives information about some radiosotopes of iridium, their masses, their half-lives, their modes of decay, their nuclear spins, and their nuclear magnetic moments.
| Isotope |
Mass |
Half-life |
Mode of decay |
Nuclear spin |
Nuclear magnetic moment |
| 188Ir |
187.95885 |
1.72 d |
EC to 188Os |
2 |
0.30 |
| 189Ir |
188.95872 |
13.2 d |
EC to 189Os |
3/2 |
0.13 |
| 190Ir |
189.9606 |
11.8 d |
EC to 190Os |
4 |
0.04 |
| 192Ir |
191.962602 |
73.83 d |
β- to 192Pt |
4 |
1.92 |
References
- Naturally occurring isotope abundances: Commission on Atomic Weights and Isotopic Abundances report for the International Union of Pure and Applied Chemistry in Isotopic Compositions of the Elements 1989, Pure and Applied Chemistry, 1998, 70, 217. [Copyright 1998 IUPAC]
- For further information about radioisotopes see Jonghwa Chang's (Korea Atomic Energy Research Institute) Table of the Nuclides
- Masses, nuclear spins, and magnetic moments: I. Mills, T. Cvitas, K. Homann, N. Kallay, and K. Kuchitsu in Quantities, Units and Symbols in Physical Chemistry, Blackwell Scientific Publications, Oxford, UK, 1988. [Copyright 1988 IUPAC]
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