Isotopes of iridium

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Isotopes of iridium (77Ir)
Main isotopes[1] Decay
Isotope abun­dance half-life (t1/2) mode pro­duct
189Ir synth 13.2 d ε 189Os
190Ir synth 11.751 d ε 190Os
191Ir 37.3% stable
192Ir synth 73.82 d β− 192Pt
ε 192Os
192m2Ir synth 241 y IT 192Ir
193Ir 62.7% stable
Standard atomic weight Ar°(Ir)

There are two natural isotopes of iridium (77Ir), 191Ir and 193Ir, both stable. In addition, there are 40 known radioisotopes with mass numbers 164 through 205, the most stable being 192Ir with a half-life of 73.82 days, and many nuclear isomers, the most stable of which is 192m2Ir with a half-life of 241 years. All other nuclides have half-lives under two weeks, 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]

The isotope 191Ir was the first one of any element to be shown to present a Mössbauer effect. This renders it useful for Mössbauer spectroscopy for research in physics, chemistry, biochemistry, metallurgy, and mineralogy.[5]

List of isotopes

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Nuclide
[n 1] 		Z N Isotopic mass (Da)[6]
[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][7] 77 87 163.99197#(34) <0.5 μs p? 163Os 2#
164mIr 163.99197#(34)
260(100)# keV 		70(10) μs p (96%) 163Os (9+)
α (4%) 160mRe
165Ir 88 165.98572#(22) 1.20+0.82
−0.74 μs[8] 		p 164Os (1/2+)
165mIr[7] 165.98572#(22)
~255 keV 		340(40) μs p (88%) 164Os (11/2)
α (12%) 161mRe
166Ir 89 165.98582#(22) 10.5(22) ms α (93%) 162Re (2)
p (7%) 165Os
166mIr 165.98582#(22)
171(6) keV 		15.1(9) ms α (98.2%) 162Re (9)+
p (1.8%) 165Os
167Ir 90 166.981672(20) 29.3(6) ms α (43.5%) 163Re 1/2+
p (38.6%) 166Os
β+ (17.9%) 167Os
167mIr 166.981672(20)
175.5(21) keV 		28.5(5) ms α (89%) 163Re 11/2
β+ (11%) 167Os
p (0.41%) 166Os
168Ir 91 167.979961(59) 230(50) ms α 164Re (2)-
168mIr[n 10] 167.979961(59)
40(250) keV 		163(16) ms α (77%) 164Re (9,10)+
β+? 168Os
β+, p? 167Re
169Ir 92 168.976282(25) 353(4) ms α (53%) 165Re (1/2+)
β+ (47%) 169Os
169mIr 168.976282(25)
153(22) keV 		280(1) ms α (79%) 165Re (11/2)
β+? 169Os
p? 168Os
170Ir 93 169.97511#(11) 910(150) ms β+ (94.8%) 170Os (3)
α (5.2%) 166Re
170mIr[n 10] 169.97511#(11)
40(50)# keV 		811(18) ms α (38%) 166Re (8+)
β+? 170Os
IT? 170Ir
171Ir 94 170.971646(41) 3.1(3) s β+ (85%) 171Os 1/2+
α (15%) 167Re
171mIr 170.971646(41)
164(11)# keV 		1.47(6) s α (54%) 167Re (11/2)
β+? 171Os
p? 170Os
172Ir 95 171.970607(35) 4.4(3) s β+ (~98%) 172Os (3,4)
α (~2%) 168Re
172mIr 171.970607(35)
139(10) keV 		2.19(7) s β+ (90.5%) 172Os (7+)
α (9.5%) 168Re
173Ir 96 172.967505(11) 9.0(8) s β+ (96.5%) 173Os (1/2+,3/2+)
α (3.5%) 169Re
173mIr 172.967505(11)
226(9) keV 		2.20(5) s β+ (88%) 173Os 11/2
α (12%) 169Re
174Ir 97 173.966950(12) 7.9(6) s β+ (99.5%) 174Os (2+,3)
α (0.5%) 170Re
174mIr 173.966950(12)
124(16) keV 		4.9(3) s β+ (97.5%) 174Os (6,7,8,9)
α (2.5%) 170Re
175Ir 98 174.964150(13) 9(2) s β+ (99.15%) 175Os (1/2+)
α (0.85%) 171Re
175m1Ir 174.964150(13)
50(40)# keV 		33(4) s β+ 175Os 9/2#
175m2Ir 174.964150(13)
97.4(7) keV 		6.58(15) μs IT 175Ir (5/2)
176Ir 99 175.9636263(87) 8.7(5) s β+ (96.9%) 176Os (3+)
α (3.1%) 172Re
177Ir 100 176.961302(21) 29.8(17) s β+ (99.94%) 177Os 5/2
α (0.06%) 173Re
177mIr 176.961302(21)
180.9(4) keV 		>100 ns IT 177Ir (5/2+)
178Ir 101 177.961079(20) 12(2) s β+ 178Os 3+#
179Ir 102 178.959118(10) 79(1) s β+ 179Os (5/2)
180Ir 103 179.959229(23) 1.5(1) min β+ 180Os (5+)
181Ir 104 180.9576347(56) 4.90(15) min β+ 181Os 5/2
181m1Ir 180.9576347(56)
289.33(13) keV 		298 ns IT 181Ir 5/2+
181m2Ir 180.9576347(56)
366.30(22) keV 		126(6) ns IT 181Ir 9/2
182Ir 105 181.958076(23) 15.0(10) min β+ 182Os 3+
182m1Ir 181.958076(23)
71.02(17) keV 		170(40) ns IT 182Ir (5)+
182m2Ir 181.958076(23)
176.4(3) keV 		130(50) ns IT 182Ir (6)
183Ir 106 182.956841(26) 58(5) min β+ 183Os 5/2
184Ir 107 183.957476(30) 3.09(3) h β+ 184Os 5
184m1Ir 183.957476(30)
225.65(11) keV 		470(30) μs IT 184Ir 3+
184m2Ir 183.957476(30)
328.40(24) keV 		350(90) ns IT 184Ir 7+
185Ir 108 184.956698(30) 14.4(1) h β+ 185Os 5/2
185mIr 184.956698(30)
2197(23) keV 		120(20) ns IT 185Ir (23/2,25/2)#
186Ir 109 185.957947(18) 16.64(3) h β+ 186Os 5+
186mIr 185.957947(18)
0.8(4) keV 		1.92(5) h β+ (~75%) 186Os 2
IT (~25%) 186Ir
187Ir 110 186.957542(30) 10.5(3) h β+ 187Os 3/2+
187m1Ir 186.957542(30)
186.16(4) keV 		30.3(6) ms IT 187Ir 9/2
187m2Ir 186.957542(30)
433.75(6) keV 		152(12) ns IT 187Ir 11/2
187m3Ir 186.957542(30)
2487.7(4) keV 		1.8(5) μs IT 187Ir 29/2
188Ir 111 187.958835(10) 41.5(5) h β+ 188Os 1
188mIr 187.958835(10)
964(23) keV 		4.15(15) ms IT 188Ir 11#
189Ir 112 188.958723(14) 13.2(1) d EC 189Os 3/2+
189m1Ir 188.958723(14)
372.17(4) keV 		13.3(3) ms IT 189Ir 11/2
189m2Ir 188.958723(14)
2332.8(3) keV 		3.7(2) ms IT 189Ir 25/2+
190Ir 113 189.9605434(15) 11.7511(20) d[9] EC 190Os 4
β+ (<0.002%)[9]
190m1Ir 189.9605434(15)
26.1(1) keV 		1.120(3) h IT 190Ir 1
190m2Ir 189.9605434(15)
36.154(25) keV 		>2 μs IT 190Ir 4+
190m3Ir 189.9605434(15)
376.4(1) keV 		3.087(12) h EC (91.4%) 190Os 11
IT (8.6%) 190Ir
191Ir 114 190.9605915(14) Observationally Stable[n 11] 3/2+ 0.373(2)
191m1Ir 190.9605915(14)
171.29(4) keV 		4.899(23) s IT 191Ir 11/2
191m2Ir 190.9605915(14)
2101.0(9) keV 		5.7(4) s IT 191Ir 31/2(+)
192Ir 115 191.9626024(14) 73.820(14) d β (95.24%) 192Pt 4+
EC (4.76%) 192Os
192m1Ir 191.9626024(14)
56.720(5) keV 		1.45(5) min IT (99.98%) 192Ir 1
β (0.0175%) 192Pt
192m2Ir 191.9626024(14)
168.14(12) keV 		241(9) y IT 192Ir (11)
193Ir 116 192.9629238(14) Observationally Stable[n 12] 3/2+ 0.627(2)
193m1Ir 192.9629238(14)
80.238(6) keV 		10.53(4) d IT 193Ir 11/2
193m2Ir 192.9629238(14)
2278.9(5) keV 		124.8(21) μs IT 193Ir 31/2+
194Ir 117 193.9650757(14) 19.35(7) h β 194Pt 1
194m1Ir 193.9650757(14)
147.072(2) keV 		31.85(24) ms IT 194Ir 4+
194m2Ir 193.9650757(14)
370(70) keV 		171(11) d β 194Pt (11)
195Ir 118 194.9659769(14) 2.29(17) h β 195Pt 3/2+
195m1Ir 194.9659769(14)
100(5) keV 		3.74(7) h β 195Pt 11/2
195m2Ir 194.9659769(14)
2354(6) keV 		4.4(6) μs IT 195Ir (27/2+)
196Ir 119 195.968400(41) 52.0(11) s β 196Pt (1,2)
196mIr 195.968400(41)
210(40) keV 		1.40(2) h β 196Pt 11#
197Ir 120 196.969657(22) 5.8(5) min β 197Pt 3/2+
197m1Ir 196.969657(22)
115(5) keV 		8.9(3) min β 197Pt 11/2
197m2Ir 196.969657(22)
1700(500)# keV 		30(8) μs IT 197Ir
197m3Ir 196.969657(22)
2800(500)# keV 		15(9) μs IT 197Ir
198Ir 121 197.97240#(22) 8.7(4) s β 198Pt 1
199Ir 122 198.973807(44) 7(5) s β 199Pt 3/2+#
200Ir 123 199.97684#(21) 43(6) s β 200Pt (2, 3)
201Ir 124 200.97870#(22) 21(5) s β 201Pt (3/2+)
202Ir 125 201.98214#(32) 11(3) s β 202Pt (2)
202mIr 201.98214#(32)
2600(300)# keV 		3.4(6) μs IT 202Ir
203Ir 126 202.98457#(43) 7# s [>300 ns] 3/2+#
203mIr 202.98457#(43)
2140(50)# keV 		798(350) ns IT 203Ir
204Ir 127 203.98973#(43) 2# s [>300 ns] 3/2+#
205Ir 128 204.99399#(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. ^ a b c # – 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. ^ a b Order of ground state and isomer is uncertain.
  11. ^ Believed to undergo α decay to 187Re[10][11]
  12. ^ Believed to undergo α decay to 189Re[10]

Iridium-192

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Main article: Iridium-192

Iridium-192 (symbol 192Ir) is a radioactive isotope of iridium, with a half-life of 73.82 days.[12] It decays by emitting beta (β) particles and gamma (γ) radiation. 95.24% of 192Ir decays occur via β- emission, leading to 192Pt; the remaining 4.76% occur via electron capture to 192Os; both modes involve gamma emission. Iridium-192 is normally produced by neutron activation of natural-abundance iridium metal.[13]

Iridium-192 is used in brachytherapy and in industrial radiography, particularly for nondestructive testing of welds in steel in the oil and gas industries.

See also

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Daughter products other than iridium

References

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  1. ^ a b c d e 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. ^ Chereminisoff, N. P. (1990). Handbook of Ceramics and Composites. CRC Press. p. 424. ISBN 978-0-8247-8006-7.
  6. ^ 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.
  7. ^ a b 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.
  8. ^ 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.
  9. ^ a b Janiak, Ł.; Gierlik, M.; Kosinski, T.; Matusiak, M.; Madejowski, G.; Wronka, S.; Rzadkiewicz, J. (2024). "Half-life of 190Ir". Physical Review C. 110 (14306) 014306. Bibcode:2024PhRvC.110a4306J. doi:10.1103/PhysRevC.110.014306.
  10. ^ a b 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.
  11. ^ Belli, P.; Bernabei, R.; Danevich, F. A.; et al. (2019). "Experimental searches for rare alpha and beta decays". European Physical Journal A. 55 (8): 14011407. arXiv:1908.11458. Bibcode:2019EPJA...55..140B. doi:10.1140/epja/i2019-12823-2. ISSN 1434-601X. S2CID 201664098.
  12. ^ "Radioisotope Brief: Iridium-192 (Ir-192)". Retrieved 20 March 2012.
  13. ^ "Isotope Supplier: Stable Isotopes and Radioisotopes from ISOFLEX - Iridium-192". www.isoflex.com. Retrieved 2017-10-11.
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