Isotopes of iridium

Main isotopes of iridium (₇₇Ir)
ε	192Os
Standard atomic weight (Ar, standard)	192.217(3)[1];

There are two natural isotopes of iridium (₇₇Ir), and 34 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.

Iridium-192

Iridium-192 (symbol ¹⁹²Ir) is a radioactive isotope of iridium, with a half-life of 73.83 days.^[2] 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.^[3] Iridium-192 is normally produced by neutron activation of natural-abundance iridium metal.^[4]

Iridium-192 is a very strong gamma ray emitter, with a gamma dose-constant of approximately 0.591 Rem/hr at one meter, and a specific activity of 9.22 kCi/g.^[5]^[6] There are seven principal energy packets produced during its disintegration process ranging from just over 0.2 to about 0.6 MeV. Iridium-192 is commonly used as a gamma ray source in industrial radiography to locate flaws in metal components.^[7] It is also used in radiotherapy as a radiation source, in particular in brachytherapy.

Iridium-192 has accounted for the majority of cases tracked by the U.S Nuclear Regulatory Commission in which radioactive materials have gone missing in quantities large enough to make a dirty bomb.^[8]

List of isotopes

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)^[9]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin and parity	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	decay mode(s)^[9]^{[n 1]}	daughter isotope(s)^{[n 2]}	nuclear spin and parity	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
¹⁶⁴Ir	77	87	163.99220(44)#	1# ms			2−#
^164mIr	270(110)# keV			94(27) µs			9+#
¹⁶⁵Ir	77	88	164.98752(23)#	<1# µs	p	¹⁶⁴Os	1/2+#
¹⁶⁵Ir	77	88	164.98752(23)#	<1# µs	α (rare)	¹⁶¹Re	1/2+#
^165mIr	180(50)# keV			300(60) µs	p (87%)	¹⁶⁴Os	11/2−
^165mIr	180(50)# keV			300(60) µs	α (13%)	¹⁶¹Re	11/2−
¹⁶⁶Ir	77	89	165.98582(22)#	10.5(22) ms	α (93%)	¹⁶²Re	(2−)
¹⁶⁶Ir	77	89	165.98582(22)#	10.5(22) ms	p (7%)	¹⁶⁵Os	(2−)
^166mIr	172(6) keV			15.1(9) ms	α (98.2%)	¹⁶²Re	(9+)
^166mIr	172(6) keV			15.1(9) ms	p (1.8%)	¹⁶⁵Os	(9+)
¹⁶⁷Ir	77	90	166.981665(20)	35.2(20) ms	α (48%)	¹⁶³Re	1/2+
					p (32%)	¹⁶⁶Os
					β⁺ (20%)	¹⁶⁷Os
^167mIr	175.3(22) keV			30.0(6) ms	α (80%)	¹⁶³Re	11/2−
					β⁺ (20%)	¹⁶⁷Os
					p (.4%)	¹⁶⁶Os
¹⁶⁸Ir	77	91	167.97988(16)#	161(21) ms	α	¹⁶⁴Re	high
¹⁶⁸Ir	77	91	167.97988(16)#	161(21) ms	β⁺ (rare)	¹⁶⁸Os	high
^168mIr	50(100)# keV			125(40) ms	α	¹⁶⁴Re	low
¹⁶⁹Ir	77	92	168.976295(28)	780(360) ms [0.64(+46−24) s]	α	¹⁶⁵Re	1/2+#
¹⁶⁹Ir	77	92	168.976295(28)	780(360) ms [0.64(+46−24) s]	β⁺ (rare)	¹⁶⁹Os	1/2+#
^169mIr	154(24) keV			308(22) ms	α (72%)	¹⁶⁵Re	11/2−#
^169mIr	154(24) keV			308(22) ms	β⁺ (28%)	¹⁶⁹Os	11/2−#
¹⁷⁰Ir	77	93	169.97497(11)#	910(150) ms [0.87(+18−12) s]	β⁺ (64%)	¹⁷⁰Os	low#
¹⁷⁰Ir	77	93	169.97497(11)#	910(150) ms [0.87(+18−12) s]	α (36%)	¹⁶⁶Re	low#
^170mIr	270(70)# keV			440(60) ms			high#
¹⁷¹Ir	77	94	170.97163(4)	3.6(10) s [3.2(+13−7) s]	α (58%)	¹⁶⁷Re	1/2+#
¹⁷¹Ir	77	94	170.97163(4)	3.6(10) s [3.2(+13−7) s]	β⁺ (42%)	¹⁷¹Os	1/2+#
^171mIr	180(30)# keV			1.40(10) s			(11/2−)
¹⁷²Ir	77	95	171.97046(11)#	4.4(3) s	β⁺ (98%)	¹⁷²Os	(3+)
¹⁷²Ir	77	95	171.97046(11)#	4.4(3) s	α (2%)	¹⁶⁸Re	(3+)
^172mIr	280(100)# keV			2.0(1) s	β⁺ (77%)	¹⁷²Os	(7+)
^172mIr	280(100)# keV			2.0(1) s	α (23%)	¹⁶⁸Re	(7+)
¹⁷³Ir	77	96	172.967502(15)	9.0(8) s	β⁺ (93%)	¹⁷³Os	(3/2+,5/2+)
¹⁷³Ir	77	96	172.967502(15)	9.0(8) s	α (7%)	¹⁶⁹Re	(3/2+,5/2+)
^173mIr	253(27) keV			2.20(5) s	β⁺ (88%)	¹⁷³Os	(11/2−)
^173mIr	253(27) keV			2.20(5) s	α (12%)	¹⁶⁹Re	(11/2−)
¹⁷⁴Ir	77	97	173.966861(30)	7.9(6) s	β⁺ (99.5%)	¹⁷⁴Os	(3+)
¹⁷⁴Ir	77	97	173.966861(30)	7.9(6) s	α (.5%)	¹⁷⁰Re	(3+)
^174mIr	193(11) keV			4.9(3) s	β⁺ (99.53%)	¹⁷⁴Os	(7+)
^174mIr	193(11) keV			4.9(3) s	α (.47%)	¹⁷⁰Re	(7+)
¹⁷⁵Ir	77	98	174.964113(21)	9(2) s	β⁺ (99.15%)	¹⁷⁵Os	(5/2−)
¹⁷⁵Ir	77	98	174.964113(21)	9(2) s	α (.85%)	¹⁷¹Re	(5/2−)
¹⁷⁶Ir	77	99	175.963649(22)	8.3(6) s	β⁺ (97.9%)	¹⁷⁶Os
¹⁷⁶Ir	77	99	175.963649(22)	8.3(6) s	α (2.1%)	¹⁷²Re
¹⁷⁷Ir	77	100	176.961302(21)	30(2) s	β⁺ (99.94%)	¹⁷⁷Os	5/2−
¹⁷⁷Ir	77	100	176.961302(21)	30(2) s	α (.06%)	¹⁷³Re	5/2−
¹⁷⁸Ir	77	101	177.961082(21)	12(2) s	β⁺	¹⁷⁸Os
¹⁷⁹Ir	77	102	178.959122(12)	79(1) s	β⁺	¹⁷⁹Os	(5/2)−
¹⁸⁰Ir	77	103	179.959229(23)	1.5(1) min	β⁺	¹⁸⁰Os	(4,5)(+#)
¹⁸¹Ir	77	104	180.957625(28)	4.90(15) min	β⁺	¹⁸¹Os	(5/2)−
¹⁸²Ir	77	105	181.958076(23)	15(1) min	β⁺	¹⁸²Os	(3+)
¹⁸³Ir	77	106	182.956846(27)	57(4) min	β⁺ ( 99.95%)	¹⁸³Os	5/2−
¹⁸³Ir	77	106	182.956846(27)	57(4) min	α (.05%)	¹⁷⁹Re	5/2−
¹⁸⁴Ir	77	107	183.95748(3)	3.09(3) h	β⁺	¹⁸⁴Os	5−
^184m1Ir	225.65(11) keV			470(30) µs			3+
^184m2Ir	328.40(24) keV			350(90) ns			(7)+
¹⁸⁵Ir	77	108	184.95670(3)	14.4(1) h	β⁺	¹⁸⁵Os	5/2−
¹⁸⁶Ir	77	109	185.957946(18)	16.64(3) h	β⁺	¹⁸⁶Os	5+
^186mIr	0.8(4) keV			1.92(5) h	β⁺	¹⁸⁶Os	2−
^186mIr	0.8(4) keV			1.92(5) h	IT (rare)	¹⁸⁶Ir	2−
¹⁸⁷Ir	77	110	186.957363(7)	10.5(3) h	β⁺	¹⁸⁷Os	3/2+
^187m1Ir	186.15(4) keV			30.3(6) ms	IT	¹⁸⁷Ir	9/2−
^187m2Ir	433.81(9) keV			152(12) ns			11/2−
¹⁸⁸Ir	77	111	187.958853(8)	41.5(5) h	β⁺	¹⁸⁸Os	1−
^188mIr	970(30) keV			4.2(2) ms	IT	¹⁸⁸Ir	7+#
^188mIr	970(30) keV			4.2(2) ms	β⁺ (rare)	¹⁸⁸Os	7+#
¹⁸⁹Ir	77	112	188.958719(14)	13.2(1) d	EC	¹⁸⁹Os	3/2+
^189m1Ir	372.18(4) keV			13.3(3) ms	IT	¹⁸⁹Ir	11/2−
^189m2Ir	2333.3(4) keV			3.7(2) ms			(25/2)+
¹⁹⁰Ir	77	113	189.9605460(18)	11.78(10) d	β⁺	¹⁹⁰Os	4−
^190m1Ir	26.1(1) keV			1.120(3) h	IT	¹⁹⁰Ir	(1−)
^190m2Ir	36.154(25) keV			>2 µs			(4)+
^190m3Ir	376.4(1) keV			3.087(12) h			(11)−
¹⁹¹Ir	77	114	190.9605940(18)	Observationally Stable^{[n 3]}			3/2+	0.373(2)
^191m1Ir	171.24(5) keV			4.94(3) s	IT	¹⁹¹Ir	11/2−
^191m2Ir	2120(40) keV			5.5(7) s
¹⁹²Ir	77	115	191.9626050(18)	73.827(13) d	β⁻ (95.24%)	¹⁹²Pt	4+
¹⁹²Ir	77	115	191.9626050(18)	73.827(13) d	EC (4.76%)	¹⁹²Os	4+
^192m1Ir	56.720(5) keV			1.45(5) min			1−
^192m2Ir	168.14(12) keV			241(9) y			(11−)
¹⁹³Ir	77	116	192.9629264(18)	Observationally Stable^{[n 4]}			3/2+	0.627(2)
^193mIr	80.240(6) keV			10.53(4) d	IT	¹⁹³Ir	11/2−
¹⁹⁴Ir	77	117	193.9650784(18)	19.28(13) h	β⁻	¹⁹⁴Pt	1−
^194m1Ir	147.078(5) keV			31.85(24) ms	IT	¹⁹⁴Ir	(4+)
^194m2Ir	370(70) keV			171(11) d			(10,11)(−#)
¹⁹⁵Ir	77	118	194.9659796(18)	2.5(2) h	β⁻	¹⁹⁵Pt	3/2+
^195mIr	100(5) keV			3.8(2) h	β⁻ (95%)	¹⁹⁵Pt	11/2−
^195mIr	100(5) keV			3.8(2) h	IT (5%)	¹⁹⁵Ir	11/2−
¹⁹⁶Ir	77	119	195.96840(4)	52(1) s	β⁻	¹⁹⁶Pt	(0−)
^196mIr	210(40) keV			1.40(2) h	β⁻ (99.7%)	¹⁹⁶Pt	(10,11−)
^196mIr	210(40) keV			1.40(2) h	IT	¹⁹⁶Ir	(10,11−)
¹⁹⁷Ir	77	120	196.969653(22)	5.8(5) min	β⁻	¹⁹⁷Pt	3/2+
^197mIr	115(5) keV			8.9(3) min	β⁻ (99.75%)	¹⁹⁷Pt	11/2−
^197mIr	115(5) keV			8.9(3) min	IT (.25%)	¹⁹⁷Ir	11/2−
¹⁹⁸Ir	77	121	197.97228(21)#	8(1) s	β⁻	¹⁹⁸Pt
¹⁹⁹Ir	77	122	198.97380(4)	20# s	β⁻	¹⁹⁹Pt	3/2+#

↑ Abbreviations:
EC: Electron capture
IT: Isomeric transition
↑ Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
↑ Believed to undergo α decay to ¹⁸⁷Re
↑ Believed to undergo α decay to ¹⁸⁹Re

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

↑ Meija, J.; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
↑ "Radioisotope Brief: Iridium-192 (Ir-192)". Retrieved 20 March 2012.
↑ Braggerly, L. L. (1956). "The radioactive decay of Iridium-192 (Pd.D. Thesis)" (PDF). Pasadena, Calif.: California Institute of Technology: 1, 2, 7.
↑ "Isotope Supplier: Stable Isotopes and Radioisotopes from ISOFLEX - Iridium-192". www.isoflex.com. Retrieved 2017-10-11.
↑ https://www.orau.org/documents/ivhp/health-physics/ornl-rsic-45.pdf
↑ http://www.hpschapters.org/northcarolina/NSDS/192Irgeneric.docx
↑ Charles Hellier (2003). Handbook of Nondestructive Evaluation. McGraw-Hill. p. 6.20. ISBN 0-07-028121-1.
↑ Steve Coll (March 12, 2007). "The Unthinkable". The New Yorker. Retrieved 2007-03-09.
↑ "Universal Nuclide Chart". nucleonica. (Registration required (help)).

Isotope masses from:
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. Check date values in: |accessdate= (help)
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.

External links

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

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.

[10] Abbreviations:
EC: Electron capture
IT: Isomeric transition

[11] Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)

[12] Believed to undergo α decay to ¹⁸⁷Re

[13] Believed to undergo α decay to ¹⁸⁹Re

[CIAAW2016-1] Meija, J.; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

[2] "Radioisotope Brief: Iridium-192 (Ir-192)". Retrieved 20 March 2012.

[3] Braggerly, L. L. (1956). "The radioactive decay of Iridium-192 (Pd.D. Thesis)" (PDF). Pasadena, Calif.: California Institute of Technology: 1, 2, 7.

[4] "Isotope Supplier: Stable Isotopes and Radioisotopes from ISOFLEX - Iridium-192". www.isoflex.com. Retrieved 2017-10-11.

[5] ttps://www.orau.org/documents/ivhp/health-physics/ornl-rsic-45.pdf

[6] ttp://www.hpschapters.org/northcarolina/NSDS/192Irgeneric.docx

[7] Charles Hellier (2003). Handbook of Nondestructive Evaluation. McGraw-Hill. p. 6.20. ISBN 0-07-028121-1.

[8] Steve Coll (March 12, 2007). "The Unthinkable". The New Yorker. Retrieved 2007-03-09.

[9] "Universal Nuclide Chart". nucleonica. (Registration required (help)).