Isotopes of iridium

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Isotopes of iridium  (77Ir)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
191Ir37.3% stable
192Ir synth73.827 d β− 192Pt
ε 192Os
192m2Irsynth241 y IT 192Ir
193Ir62.7%stable
Standard atomic weight Ar°(Ir)

There are two natural isotopes of iridium (77Ir), and 37 radioisotopes, the most stable radioisotope being 192Ir with a half-life of 73.83 days, and many nuclear 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 or observationally stable, meaning that they are predicted to be radioactive but no actual decay has been observed. [4]

Contents

List of isotopes


Nuclide
[n 1] 		Z N Isotopic mass (Da) [5]
[n 2] [n 3] 		Half-life [1]
[n 4] 		Decay
mode [1]
[n 5] 		Daughter
isotope
[n 6] [n 7] 		Spin and
parity [1]
[n 8] [n 4] 		Natural abundance (mole fraction)
Excitation energy [n 4] Normal proportion [1] Range of variation
164Ir [n 9] [6] 7787163.99197(34)#<0.5 μs p?163Os2−#
164mIr260(100)# keV70(10) μsp (96%)163Os(9+)
α (4%)160mRe
165Ir7788165.98572(22)#1.20+0.82
−0.74 μs [7] 		p164Os(1/2+)
165mIr [6] ~255 keV340(40) μsp (88%)164Os(11/2−)
α (12%)161mRe
166Ir7789165.98582(22)#10.5(22) msα (93%)162Re(2)−
p (7%)165Os
166mIr171(6) keV15.1(9) msα (98.2%)162Re(9)+
p (1.8%)165Os
167Ir7790166.981672(20)29.3(6) msα (43.5%)163Re1/2+
p (38.6%)166Os
β+ (17.9%)167Os
167mIr175.5(21) keV28.5(5) msα (89%)163Re11/2−
β+ (11%)167Os
p (0.41%)166Os
168Ir7791167.979961(59)230(50) msα164Re(2)-
168mIr [n 10] 40(250) keV163(16) msα (77%)164Re(9,10)+
β+?168Os
β+, p?167Re
169Ir7792168.976282(25)353(4) msα (53%)165Re(1/2+)
β+ (47%)169Os
169mIr153(22) keV280(1) msα (79%)165Re(11/2−)
β+?169Os
p?168Os
170Ir7793169.97511(11)#910(150) msβ+ (94.8%)170Os(3−)
α (5.2%)166Re
170mIr [n 10] 40(50)# keV811(18) msα (38%)166Re(8+)
β+?170Os
IT?170Ir
171Ir7794170.971646(41)3.1(3) sβ+ (85%)171Os1/2+
α (15%)167Re
171mIr164(11)# keV1.47(6) sα (54%)167Re(11/2−)
β+?171Os
p?170Os
172Ir7795171.970607(35)4.4(3) sβ+ (~98%)172Os(3−,4−)
α (~2%)168Re
172mIr139(10) keV2.19(7) sβ+ (90.5%)172Os(7+)
α (9.5%)168Re
173Ir7796172.967505(11)9.0(8) sβ+ (96.5%)173Os(1/2+,3/2+)
α (3.5%)169Re
173mIr226(9) keV2.20(5) sβ+ (88%)173Os11/2−
α (12%)169Re
174Ir7797173.966950(12)7.9(6) sβ+ (99.5%)174Os(2+,3−)
α (0.5%)170Re
174mIr124(16) keV4.9(3) sβ+ (97.5%)174Os(6,7,8,9)
α (2.5%)170Re
175Ir7798174.964150(13)9(2) sβ+ (99.15%)175Os(1/2+)
α (0.85%)171Re
175m1Ir50(40)# keV33(4) sβ+175Os9/2−#
175m2Ir97.4(7) keV6.58(15) μsIT175Ir(5/2−)
176Ir7799175.9636263(87)8.7(5) sβ+ (96.9%)176Os(3+)
α (3.1%)172Re
177Ir77100176.961302(21)29.8(17) sβ+ (99.94%)177Os5/2−
α (0.06%)173Re
177mIr180.9(4) keV>100 nsIT177Ir(5/2+)
178Ir77101177.961079(20)12(2) sβ+178Os3+#
179Ir77102178.959118(10)79(1) sβ+179Os(5/2)−
180Ir77103179.959229(23)1.5(1) minβ+180Os(5+)
181Ir77104180.9576347(56)4.90(15) minβ+181Os5/2−
181m1Ir289.33(13) keV298 nsIT181Ir5/2+
181m2Ir366.30(22) keV126(6) nsIT181Ir9/2−
182Ir77105181.958076(23)15.0(10) minβ+182Os3+
182m1Ir71.02(17) keV170(40) nsIT182Ir(5)+
182m2Ir176.4(3) keV130(50) nsIT182Ir(6−)
183Ir77106182.956841(26)58(5) minβ+183Os5/2−
184Ir77107183.957476(30)3.09(3) hβ+184Os5−
184m1Ir225.65(11) keV470(30) μsIT184Ir3+
184m2Ir328.40(24) keV350(90) nsIT184Ir7+
185Ir77108184 956698(30)14.4(1) hβ+185Os5/2−
185mIr2197(23) keV120(20) nsIT185Ir(23/2,25/2)#
186Ir77109185.957947(18)16.64(3) hβ+186Os5+
186mIr0.8(4) keV1.92(5) hβ+ (~75%)186Os2−
IT (~25%)186Ir
187Ir77110186.957542(30)10.5(3) hβ+187Os3/2+
187m1Ir186.16(4) keV30.3(6) msIT187Ir9/2−
187m2Ir433.75(6) keV152(12) nsIT187Ir11/2−
187m3Ir2487.7(4) keV1.8(5) μsIT187Ir29/2−
188Ir77111187.958835(10)41.5(5) hβ+188Os1−
188mIr964(23) keV4.15(15) msIT188Ir11−#
189Ir77112188.958723(14)13.2(1) dEC189Os3/2+
189m1Ir372.17(4) keV13.3(3) msIT189Ir11/2−
189m2Ir2332.8(3) keV3.7(2) msIT189Ir25/2+
190Ir77113189.9605434(15)11.7511(20) d [8] EC190Os4−
β+ (<0.002%) [8]
190m1Ir26.1(1) keV1.120(3) hIT190Ir1−
190m2Ir36.154(25) keV>2 μsIT190Ir4+
190m3Ir376.4(1) keV3.087(12) hEC (91.4%)190Os11−
IT (8.6%)190Ir
191Ir77114190.9605915(14) Observationally Stable [n 11] 3/2+0.373(2)
191m1Ir171.29(4) keV4.899(23) sIT191Ir11/2−
191m2Ir2101.0(9) keV5.7(4) sIT191Ir31/2(+)
192Ir 77115191.9626024(14)73.820(14) dβ− (95.24%)192Pt4+
EC (4.76%)192Os
192m1Ir56.720(5) keV1.45(5) minIT (99.98%)192Ir1−
β− (0.0175%)192Pt
192m2Ir168.14(12) keV241(9) yIT192Ir(11−)
193Ir77116192.9629238(14)Observationally Stable [n 12] 3/2+0.627(2)
193m1Ir80.238(6) keV10.53(4) dIT193Ir11/2−
193m2Ir2278.9(5) keV124.8(21) μsIT193Ir31/2+
194Ir77117193.9650757(14)19.35(7) hβ−194Pt1−
194m1Ir147.072(2) keV31.85(24) msIT194Ir4+
194m2Ir370(70) keV171(11) dβ−194Pt(11−)
195Ir77118194.9659769(14)2.29(17) hβ−195Pt3/2+
195m1Ir100(5) keV3.74(7) hβ−195Pt11/2−
195m2Ir2354(6) keV4.4(6) μsIT195Ir(27/2+)
196Ir77119195.968400(41)52.0(11) sβ−196Pt(1,2−)
196mIr210(40) keV1.40(2) hβ−196Pt11−#
197Ir77120196.969657(22)5.8(5) minβ−197Pt3/2+
197m1Ir115(5) keV8.9(3) minβ−197Pt11/2−
197m2Ir1700(500)# keV30(8) μsIT197Ir
197m3Ir2800(500)# keV15(9) μsIT197Ir
198Ir77121197.97240(22)#8.7(4) sβ−198Pt1−
199Ir77122198.973807(44)7(5) sβ−199Pt3/2+#
200Ir77123199.97684(21)#43(6) sβ−200Pt(2-, 3-)
201Ir77124200.97870(22)#21(5) sβ−201Pt(3/2+)
202Ir77125201.98214(32)#11(3) sβ−202Pt(2-)
202mIr2600(300)# keV3.4(6) μsIT202Ir
203Ir77126202.98457(43)#7# s
[>300 ns]		3/2+#
203mIr2140(50)# keV798(350) nsIT203Ir
204Ir77127203.98973(43)#2# s
[>300 ns]		3/2+#
205Ir77125204.99399(54)#1# s
[>300 ns]		3/2+#
This table header & footer:
  1. ↑ mIr – Excited nuclear isomer.
  2. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  3. ↑ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
  4. 1 2 3 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. ↑ Modes of decay:
    α: Alpha decay
    β+: Positron emission
    EC: Electron capture
    β−: Beta decay
    IT: Isomeric transition
    p: Proton emission
  6. ↑ Bold italics symbol as daughter – Daughter product is nearly stable.
  7. ↑ Bold symbol as daughter – Daughter product is stable.
  8. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  9. ↑ Discovery of this isotope is unconfirmed
  10. 1 2 Order of ground state and isomer is uncertain.
  11. ↑ Believed to undergo α decay to 187Re [9] [10]
  12. ↑ Believed to undergo α decay to 189Re [9]

Iridium-192

Iridium-192 (symbol 192Ir) is a radioactive isotope of iridium, with a half-life of 73.83 days. [11] It decays by emitting beta (β) particles and gamma (γ) radiation. About 96% of 192Ir decays occur via emission of β and γ radiation, leading to 192Pt. Some of the β particles are captured by other 192Ir nuclei, which are then converted to 192Os. Electron capture is responsible for the remaining 4% of 192Ir decays. [12] Iridium-192 is normally produced by neutron activation of natural-abundance iridium metal. [13]

Iridium-192 is a very strong gamma ray emitter, with a gamma dose-constant of approximately 1.54 μSv·h−1·MBq −1 at 30 cm, and a specific activity of 341 TBq·g−1 (9.22 kCi·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.

References

  1. 1 2 3 4 5 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.
  2. ↑ "Standard Atomic Weights: Iridium". CIAAW. 2017.
  3. ↑ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN   1365-3075.
  4. ↑ Belli, P.; Bernabei, R.; Danevich, F. A.; et al. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (8): 140–1–140–7. arXiv: 1908.11458 . Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. ISSN   1434-601X. S2CID   201664098.
  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.
  6. 1 2 Drummond, M. C.; O'Donnell, D.; Page, R. D.; Joss, D. T.; Capponi, L.; Cox, D. M.; Darby, I. G.; Donosa, L.; Filmer, F.; Grahn, T.; Greenlees, P. T.; Hauschild, K.; Herzan, A.; Jakobsson, U.; Jones, P. M.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Lopez-Martens, A.; Mistry, A. K.; Nieminen, P.; Peura, P.; Rahkila, P.; Rinta-Antila, S.; Ruotsalainen, P.; Sandzelius, M.; Sarén, J.; Sayğı, B.; Scholey, C.; Simpson, J.; Sorri, J.; Thornthwaite, A.; Uusitalo, J. (16 June 2014). "α decay of the π h 11 / 2 isomer in Ir 164". Physical Review C. 89 (6): 064309. Bibcode:2014PhRvC..89f4309D. doi:10.1103/PhysRevC.89.064309. ISSN   0556-2813 . Retrieved 21 June 2023.
  7. ↑ Hilton, Joshua Ben. "Decays of new nuclides 169Au, 170Hg, 165Pt and the ground state of 165Ir discovered using MARA". University of Liverpool. ProQuest   2448649087 . Retrieved 21 June 2023.
  8. 1 2 Janiak, Ł.; Gierlik, M.; Kosinski, T.; Matusiak, M.; Madejowski, G.; Wronka, S.; Rzadkiewicz, J. (2024). "Half-life of 190Ir". Physical Review C. 110 (014306). doi:10.1103/PhysRevC.110.014306.
  9. 1 2 Danevich, F. A.; Andreotti, E.; Hult, M.; Marissens, G.; Tretyak, V. I.; Yuksel, A. (2012). "Search for α decay of 151Eu to the first excited level of 147Pm using underground γ-ray spectrometry". European Physical Journal A . 48 (157): 157. arXiv: 1301.3465 . Bibcode:2012EPJA...48..157D. doi:10.1140/epja/i2012-12157-7. S2CID   118657922.
  10. ↑ Belli, P.; Bernabei, R.; Danevich, F. A.; et al. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (8): 140–1–140–7. arXiv: 1908.11458 . Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. ISSN   1434-601X. S2CID   201664098.
  11. ↑ "Radioisotope Brief: Iridium-192 (Ir-192)" . Retrieved 20 March 2012.
  12. ↑ Baggerly, Leo L. (1956). The radioactive decay of Iridium-192 (PDF) (Ph.D. thesis). Pasadena, Calif.: California Institute of Technology. pp. 1, 2, 7. doi:10.7907/26VA-RB25.
  13. ↑ "Isotope Supplier: Stable Isotopes and Radioisotopes from ISOFLEX - Iridium-192". www.isoflex.com. Retrieved 2017-10-11.
  14. ↑ Delacroix, D; Guerre, J P; Leblanc, P; Hickman, C (2002). Radionuclide and Radiation Protection Data Handbook (PDF). Radiation Protection Dosimetry. Vol. 98, no. 1 (2nd ed.). Ashford, Kent: Nuclear Technology Publishing. pp. 9–168. doi:10.1093/OXFORDJOURNALS.RPD.A006705. ISBN   1870965876. PMID   11916063. S2CID   123447679. Archived from the original (PDF) on 2019-08-22.
  15. ↑ Unger, L M; Trubey, D K (May 1982). Specific Gamma-Ray Dose Constants for Nuclides Important to Dosimetry and Radiological Assessment (PDF) (Report). Oak Ridge National Laboratory. Archived from the original (PDF) on 22 March 2018.
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