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Isotopes of Iridium

List, data and properties of all known isotopes of Iridium.

Content
Atomic properties
Decay properties
NMR active nuclides
Radiation protection
References
Iridium isotopes

All atomic nuclei of the chemical element iridium are summarized under iridium isotopes; these all consist of an atomic nucleus with 77 protons and, in the uncharged state, 77 electrons. The difference between the individual iridium isotopes is based on the number of neutrons in the nucleus.

 

Naturally Occurring Iridium Isotopes

Natural iridium is composed of the two stable isotopes iridium-191 and -193 in the following ratio:

Atomic Mass maQuantityHalf-lifeSpin
Iridium
Isotopic mixture		192,217 u100 %
Isotope 191Ir190,96059(2) u37,3(2) %stable3/2+
Isotope 193Ir192,96292(2) u62,7(2) %stable3/2+

 

All other iridium nuclides characterized so far are unstable.

 

Isotope Table: Iridium

The two following tables list the most important data and properties of the Iridium isotopes. Further information on the individual Iridium isotopes is listed on separate pages and can be accessed via the link in column 1.

 

Atomic Properties

Isotope
Nuclide		ENAtomic Mass
[Nuclear Mass]
{Mass Excess}		Spin I
(h/2π)		Parent
123456
Iridium-16416477Ir87163.99212(34) u
[163.9498838 u]
{-7.34017 MeV}
Iridium-16516577Ir88164.98755(17) u
[164.9453138 u]
{-11.5971 MeV}		(1/2+)
Iridium-165m165m77Ir88164.98755(17) u
[164.9453138 u]
{-11.5971 MeV}		(11/2-)
Iridium-16616677Ir89165.98566(21) u
[165.9434238 u]
{-13.35762 MeV}		(2-)
Iridium-166m166m77Ir89165.98566(21) u
[165.9434238 u]
{-13.35762 MeV}		(9+)
Iridium-16716777Ir90166.981672(20) u
[166.9394358 u]
{-17.07242 MeV}		1/2+171Au
Iridium-167m167m77Ir90166.981672(20) u
[166.9394358 u]
{-17.07242 MeV}		11/2-
Iridium-16816877Ir91167.97996(6) u
[167.9377238 u]
{-18.66714 MeV}
Iridium-16816877Ir91167.97996(6) u
[167.9377238 u]
{-18.66714 MeV}
Iridium-16916977Ir92168.976281(25) u
[168.9340448 u]
{-22.09411 MeV}		(1/2+)173Au
Iridium-169m169m77Ir92168.976281(25) u
[168.9340448 u]
{-22.09411 MeV}		(11/2-)
Iridium-17017077Ir93169.97492(9) u
[169.9326838 u]
{-23.36187 MeV}		(3-)174Au
Iridium-170m170m77Ir93169.97492(9) u
[169.9326838 u]
{-23.36187 MeV}		(8+)
Iridium-17117177Ir94170.97165(4) u
[170.9294138 u]
{-26.40785 MeV}		(1/2+)175Au
Iridium-171m171m77Ir94170.97165(4) u
[170.9294138 u]
{-26.40785 MeV}		(11/2-)
Iridium-17217277Ir95171.97061(3) u
[171.9283738 u]
{-27.37661 MeV}		(3-,4-)176Au
Iridium-172m172m77Ir95171.97061(3) u
[171.9283738 u]
{-27.37661 MeV}		(7+)
Iridium-17317377Ir96172.967505(12) u
[172.9252688 u]
{-30.2689 MeV}		(3/2+,5/2+)177Au
Iridium-173m173m77Ir96172.967505(12) u
[172.9252688 u]
{-30.2689 MeV}		(11/2-)
Iridium-17417477Ir97173.966867(26) u
[173.9246308 u]
{-30.86319 MeV}		(3+)178Au
Iridium-174m174m77Ir97173.966867(26) u
[173.9246308 u]
{-30.86319 MeV}		(7+)
Iridium-17517577Ir98174.964150(13) u
[174.9219138 u]
{-33.39406 MeV}		(5/2-)179Au
Iridium-17617677Ir99175.963630(18) u
[175.9213938 u]
{-33.87844 MeV}		180Au
Iridium-17717777Ir100176.961301(21) u
[176.9190648 u]
{-36.04789 MeV}		5/2-181Au
177Pt
Iridium-17817877Ir101177.961082(21) u
[177.9188458 u]
{-36.25188 MeV}		182Au
178Pt
Iridium-17917977Ir102178.959118(10) u
[178.9168818 u]
{-38.08134 MeV}		(5/2)-183Au
179Pt
Iridium-18018077Ir103179.959229(23) u
[179.9169928 u]
{-37.97794 MeV}		(5+)184Au
180Pt
Iridium-18118177Ir104180.957635(6) u
[180.9153988 u]
{-39.46274 MeV}		5/2-185Au
181Pt
Iridium-18218277Ir105181.958076(23) u
[181.9158398 u]
{-39.05195 MeV}		3+182Pt
Iridium-18318377Ir106182.956840(26) u
[182.9146038 u]
{-40.20328 MeV}		5/2-187Au
183Pt
Iridium-18418477Ir107183.95748(3) u
[183.9152438 u]
{-39.60712 MeV}		5-184Pt
Iridium-184m1184m177Ir107183.95748(3) u
[183.9152438 u]
{-39.60712 MeV}		3+
Iridium-184m2184m277Ir107183.95748(3) u
[183.9152438 u]
{-39.60712 MeV}		(7)+
Iridium-18518577Ir108184.95670(3) u
[184.9144638 u]
{-40.33369 MeV}		5/2-185Pt
Iridium-18618677Ir109185.957947(18) u
[185.9157108 u]
{-39.17212 MeV}		5+186Pt
Iridium-186m186m77Ir109185.957947(18) u
[185.9157108 u]
{-39.17212 MeV}		2-
Iridium-18718777Ir110186.95754(3) u
[186.9153038 u]
{-39.55124 MeV}		3/2+187Pt
Iridium-187m1187m177Ir110186.95754(3) u
[186.9153038 u]
{-39.55124 MeV}		9/2-
Iridium-187m2187m277Ir110186.95754(3) u
[186.9153038 u]
{-39.55124 MeV}		11/2-
Iridium-18818877Ir111187.958835(10) u
[187.9165988 u]
{-38.34495 MeV}		1-188Pt
Iridium-18918977Ir112188.958723(14) u
[188.9164868 u]
{-38.44928 MeV}		3/2+189Pt
Iridium-189m1189m177Ir112188.958723(13) u
[188.9164868 u]
{-38.44928 MeV}		11/2-
Iridium-189m2189m277Ir112188.958723(13) u
[188.9164868 u]
{-38.44928 MeV}		(25/2)+
Iridium-19019077Ir113189.9605434(15) u
[189.9183072 u]
{-36.75359 MeV}		4-
Iridium-190m1190m177Ir113189.9605434(15) u
[189.9183072 u]
{-36.75359 MeV}		(1-)
Iridium-190m2190m277Ir113189.9605434(15) u
[189.9183072 u]
{-36.75359 MeV}		(11)-
Iridium-19119177Ir114190.96059(2) u
[190.9183538 u]
{-36.71018 MeV}		3/2+191Os
191Pt
Iridium-191m1191m177Ir114190.96059(2) u
[190.9183538 u]
{-36.71018 MeV}		11/2-
Iridium-191m2191m277Ir114190.96059(2) u
[190.9183538 u]
{-36.71018 MeV}
Iridium-19219277Ir115191.9626025(14) u
[191.9203663 u]
{-34.83555 MeV}		4+
Iridium-192m1192m177Ir115191.9626025(14) u
[191.9203663 u]
{-34.83555 MeV}		1-
Iridium-192m2192m277Ir115191.9626025(14) u
[191.9203663 u]
{-34.83555 MeV}		(11-)
Iridium-19319377Ir116192.96292(2) u
[192.9206838 u]
{-34.5398 MeV}		3/2+193Os
193Pt
Iridium-193m193m77Ir116192.96292(2) u
[192.9206838 u]
{-34.5398 MeV}		11/2-
Iridium-193m2193m277Ir116192.96292(2) u
[192.9206838 u]
{-34.5398 MeV}		31/2+
Iridium-19419477Ir117193.9650758(14) u
[193.9228396 u]
{-32.53168 MeV}		1-194Os
Iridium-194m1194m177Ir117193.9650758(14) u
[193.9228396 u]
{-32.53168 MeV}		4+
Iridium-194m2194m277Ir117193.9650758(14) u
[193.9228396 u]
{-32.53168 MeV}		(10,11)
Iridium-19519577Ir118194.9659770(14) u
[194.9237408 u]
{-31.69222 MeV}		3/2+
Iridium-195m195m77Ir118194.9659770(14) u
[194.9237408 u]
{-31.69222 MeV}		11/2-
Iridium-19619677Ir119195.96840(4) u
[195.9261638 u]
{-29.43521 MeV}		(0-)196Os
Iridium-196m196m77Ir119195.96840(4) u
[195.9261638 u]
{-29.43521 MeV}		(10,11-)
Iridium-19719777Ir120196.969657(22) u
[196.9274208 u]
{-28.26432 MeV}		3/2+
Iridium-197m197m77Ir120196.969657(22) u
[196.9274208 u]
{-28.26432 MeV}		11/2-
Iridium-19819877Ir121197.97228(21) u
[197.9300438 u]
{-25.82101 MeV}
Iridium-19919977Ir122198.97381(4) u
[198.9315738 u]
{-24.39583 MeV}
Iridium-20020077Ir123199.97680(21) u
[199.9345638 u]
{-21.61066 MeV}
Iridium-20120177Ir124200.97864(21) u
[200.9364038 u]
{-19.89671 MeV}
Iridium-20220277Ir125201.98199(32) u
[201.9397538 u]
{-16.77621 MeV}		(1-,2-)
Iridium-20320377Ir126202.98423(43) u
[202.9419938 u]
{-14.68966 MeV}
Iridium-20420477Ir127203.98960(43) u
[203.9473638 u]
{-9.68754 MeV}
Iridium-20520577Ir128204.99360(54) u
[204.9513638 u]
{-5.96156 MeV}

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
Ir-164α → 160Re
EC/β+ → 164Os
p → 163Os		?
?
?		6.97(10) MeV
13.08(35) MeV
AL
Ir-1651 μsα → 161Re
p → 164Os		?
?		6.82(5) MeV
AL
Ir-165m0.30(6) msp → 164Os
α → 161Re		87(4) %
13(4) %
Ir-16610.5(22) msα → 162Re
p → 165Os		93(3) %
7(3) %		6.722(6) MeV
AL
Ir-166m15.1(9) msα → 162Re
p → 165Os		98.2(6) %
1.8(6) %
Ir-16735.2(20) msα → 163Re
p → 166Os
EC/β+ → 167Os		48(6) %
32(4) %
20(10) %		6.5049(26) MeV

9.43(7) MeV		AL
Ir-167m30.0(6) msα → 163Re
EC/β+ → 167Os
p → 166Os		80(10) %
20(10) %
0.4(1) %
Ir-168222 msα → 164Re
p → 167Os
EC/β+ → 168Os		≤ 100 %
?
?		6.381(9) MeV

11.33(6) MeV		AL
Ir-168m159 msα → 164Re
p → 167Os
ε ? 168Os		77(9) %
?
23(9) %
Ir-169353(4) msα → 165Re
p → 168Os
EC/β+ → 169Os		45(12) %
?
?		6.141(4) MeV

8.63(3) MeV		AL
Ir-169m281(4) msα → 165Re
p → 168Os
EC/β+ → 169Os		72(7) %
?
?
Ir-1700.87 sα → 166Re
EC/β+ → 170Os		5.2(17) %
94.8(17) %		6.11(5) MeV
10.57(9) MeV		AL
Ir-170m811(18) msα → 166Re
EC/β+ → 170Os
Iso → 170Ir		38(5) %
?
?
Ir-1713.2 sα → 167Re
EC/β+ → 171Os		15(2) %
85(2) %		5.994(13) MeV
7.89(4) MeV		AL
Ir-171m1.2(1) sα → 167Re
EC/β+ → 171Os
p → 170Os		54(5) %
?
?
Ir-1724.4(3) sα → 168Re
EC/β+ → 172Os		ca. 2 %
ca. 98 %		5.991(10)MeV
9.86(3) MeV		AL
Ir-172m2.19(7) sα → 168Re
EC/β+ → 172Os		9.5(11) %
90.5(11) %
Ir-1739.0(8) sα → 169Re
EC/β+ → 173Os		< 7 %
> 93 %		5.716(19) MeV
7.170(19) MeV		AL
Ir-173m2.20(5) sα → 169Re
EC/β+ → 173Os		12(1) %
88(1) %
Ir-1747.9(6) sα → 170Re
EC → 174Os		0.5(3) %
99.5(3) %		5.625(10) MeV
9.132(26) MeV		AL
Ir-174m4.9(3) sα → 170Re
EC → 174Os		2.5(3) %
97.5(3) %
Ir-1759(2) sα → 171Re
EC/β+ → 175Os		0.85(28) %
99.15(28) %		5.43(3) MeV
6.711(17) MeV		AL
Ir-1768.7(5) sα → 172Re
EC/β+ → 176Os		3.1(6) %
96.9(6) %		5.23(4) MeV
8.22(3) MeV		AL
Ir-17729.8(17) sα → 173Re
EC/β+ → 177Os		0.06(1) %
99.94(1) %		5.08(3) MeV
5.909(25) MeV		AL
Ir-17812(2) sEC/β+ → 178Os100 %7.292(24) MeVAL
Ir-17979(1) sEC/β+ → 179Os100 %4.938(19) MeVAL
Ir-1801.5(1) minEC/β+ → 180Os100 %6.380(27) MeVAL
Ir-1814.90(15) minEC/β+ → 181Os100 %4.087(26) MeVAL
Ir-18215(1) minEC/β+ → 182Os100 %5.56(3) MeVAL
Ir-18358(6) minEC/β+ → 183Os100 %3.46(6) MeVAL
Ir-1843.09(3) hEC/β+ → 184Os100 %4.642(28) MeVAL
Ir-184m1470(30) μsIso → 184Ir100 %
Ir-184m2350(90) ns
Ir-18514.4(1) hEC/β+ → 185Os100 %2.470(28) MeVAL
Ir-18616.64(3) hEC/β+ → 186Os100 %3.828(17) MeVAL
Ir-186m1.90(5) hEC/β+ → 186Os
Iso → 186Ir		ca. 75 %
ca. 25 %
Ir-18710.5(3) hEC/β+ → 187Os100 %1.670(28) MeVAL
Ir-187m130.3(6) msIso → 187Ir100 %
Ir-187m2152(12) ns
Ir-18841.5(5) hEC/β+ → 188Os100 %2.792(9) MeVAL
Ir-18913.2(1) dEC → 189Os100 %0.537(13) MeVAL
Ir-189m113.3(3) msIso → 189Ir100 %
Ir-189m23.7(2) msIso → 189Ir100 %
Ir-19011.7511(20) dEC → 190Os
β+ → 190Os		> 99.99 %
< 0.002 %		1.9542(15) MeV
AL
Ir-190m11.120(3) hIso → 190Ir100 %
Ir-190m23.087(12) hIso → 190Ir
EC/β+ → 190Os		8.6(2) %
91.4(2) %
Ir-191stableAL
Ir-191m14.899(23) sIso → 191Ir100 %
Ir-191m25.5(7) sIso → 191Ir100 %
Ir-19273.829(11) dβ- → 192Pt
EC → 192Os		95.24(4) %
4.76(4) %		1.4529(23) MeV
1.0466(27) MeV		AL
Ir-192m11.45(5) minβ- → 192Pt
Iso → 192Ir		0.0175 %
99.9825 %
Ir-192m2241(9) aIso → 192Ir100 %
Ir-193stableAL
Ir-193m10.53(4) dIso → 193Ir100 %
Ir-193m2124.8(21) μsIso → 193Ir100 %
Ir-19419.28(13) hβ- → 194Pt100 %2.2284(13) MeVAL
Ir-194m131.85(24) msIso → 194Ir100 %
Ir-194m2171(11) dβ- → 194Pt100 %
Ir-1952.29(17) hβ- → 195Pt100 %1.1016(13) MeVAL
Ir-195m3.67(82) hβ- → 195Pt
Iso → 195Ir		95(5) %
5(5) %
Ir-19652(1) sβ- → 196Pt100 %3.21(4) MeVAL
Ir-196m1.40(2) hβ- → 196Pt
Iso → 196Ir		> 99.7 %
< 0.3 %
Ir-1975.8(5) minβ- → 197Pt100 %2.156(20) MeVAL
Ir-197m8.9(3) minβ- → 197Pt
Iso → 197Ir		99.75(10) %
0.25(10) %
Ir-1988(1) sβ- → 198Pt100 %4.08(20) MeVAL
Ir-1996 sβ- ? 199Pt?2.99(4) MeVAL
Ir-200300 nsβ- → 200Pt?4.99(200) MeVAL
Ir-201300 nsβ- → 201Pt?3.84(20) MeVAL
Ir-20211(3) sβ- → 202Pt100 %5.92(30) MeVAL
Ir-203160 nsβ- → 203Pt?4.94(45) MeV
Ir-204160 nsβ- → 204Pt
β-, n → 203Pt		?
?		4.94(45) MeV
1.87(45) MeV
Ir-205160 nsβ- → 205Pt
β-, n → 204Pt		?
?		7.01(58) MeV
3.89(54) MeV

 

Notes (related to the columns):

1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and Atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - relative atomic mass of the Iridium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
5 - nuclear spin I, unit: h/2π.
6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.

7 - isotope notation in short form.
8 - decay: half-live of the Iridium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

NMR active Iridium nuclides

Nuclide
quantity 1)
spin		Nuclear
magnetic
moment
μ/μN		Gyromagnetic ratio
{Quadrupole moment}		Resonant
frequency
v0 bei 1 T		Relative
sensitivity
H0 = const.
v0 = const. 3)
191Ir
37,3(2) %
3/2+		+ 0,1507(6)0,4665
{+ 0,816(9)}		0,76580,00003
0,0899
193Ir
62,7(2) %
3/2+		+ 0,1637(6)0,508
{+ 0,751(9)}		0,83190,00004
0,0977

1) Quantity Percentage of natural occurrence.

2) Gyromagnetic ratio: 107 rad T-1 s-1
    Quadrupole moment: Q [barn] = [100 fm2]

3) Related to 1H = 1,000.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Iridium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Ir-182105 Bq10 Bq/g15.0 min
Ir-184106 Bq10 Bq/g3.1 h
Ir-185106 Bq10 Bq/g14.4 h
Ir-186106 Bq10 Bq/g16.6 h
Ir-187106 Bq100 Bq/g10.5 h
Ir-188106 Bq10 Bq/g41.5 h
Ir-189+107 Bq100 Bq/g13.2 d
Ir-190+106 Bq1 Bq/g0,05 TBq1 Bq cm-211.8 d
Ir-192104 Bq1 Bq/g0,08 TBq1 Bq cm-273.8 d
Ir-192m107 Bq1000 Bq/g1.4 min
Ir-193m107 Bq10000 Bq/g10.5 d
Ir-194106 Bq0,1 Bq/g19.3 h
Ir-194m105 Bq100 Bq/g0,7 TBq10 Bq cm-2171.0 d
Ir-195106 Bq100 Bq/g2.5 h
Ir-195m+106 Bq100 Bq/g3.8 h

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Iridium nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Iridium: NMR properties - 191Ir-NMR, 193Ir-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

[9] - J. W. Arblaster:
The Discoverers of the Iridium Isotopes.
In: Platinum Metals Review, (2003).

[10] - R. Robinson, M. Thoennessen:
Discovery of tantalum, rhenium, osmium, and iridium isotopes.
In: Atomic Data and Nuclear Data Tables, (2012), DOI 10.1016/j.adt.2011.09.003.

 

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