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Isotopes of Iridium

List, data and properties of all known isotopes of Iridium as well as radioactive decay products and intermediate products.

 

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

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
164Ir7716487Iridium-164163.99212(34) u
[163.9498838 u]
{-7.34017 MeV}
165Ir7716588Iridium-165164.98755(17) u
[164.9453138 u]
{-11.5971 MeV}
(1/2+)
165mIr7716588Iridium-165m164.98755(17) u
[164.9453138 u]
{-11.5971 MeV}
(11/2-)
166Ir7716689Iridium-166165.98566(21) u
[165.9434238 u]
{-13.35762 MeV}
(2-)
166mIr7716689Iridium-166m165.98566(21) u
[165.9434238 u]
{-13.35762 MeV}
(9+)
167Ir7716790Iridium-167166.981672(20) u
[166.9394358 u]
{-17.07242 MeV}
1/2+171Au
167mIr7716790Iridium-167m166.981672(20) u
[166.9394358 u]
{-17.07242 MeV}
11/2-
168Ir7716891Iridium-168167.97996(6) u
[167.9377238 u]
{-18.66714 MeV}
168Ir7716891Iridium-168167.97996(6) u
[167.9377238 u]
{-18.66714 MeV}
169Ir7716992Iridium-169168.976281(25) u
[168.9340448 u]
{-22.09411 MeV}
(1/2+)173Au
169mIr7716992Iridium-169m168.976281(25) u
[168.9340448 u]
{-22.09411 MeV}
(11/2-)
170Ir7717093Iridium-170169.97492(9) u
[169.9326838 u]
{-23.36187 MeV}
(3-)174Au
170mIr7717093Iridium-170m169.97492(9) u
[169.9326838 u]
{-23.36187 MeV}
(8+)
171Ir7717194Iridium-171170.97165(4) u
[170.9294138 u]
{-26.40785 MeV}
(1/2+)175Au
171mIr7717194Iridium-171m170.97165(4) u
[170.9294138 u]
{-26.40785 MeV}
(11/2-)
172Ir7717295Iridium-172171.97061(3) u
[171.9283738 u]
{-27.37661 MeV}
(3-,4-)176Au
172mIr7717295Iridium-172m171.97061(3) u
[171.9283738 u]
{-27.37661 MeV}
(7+)
173Ir7717396Iridium-173172.967505(12) u
[172.9252688 u]
{-30.2689 MeV}
(3/2+,5/2+)177Au
173mIr7717396Iridium-173m172.967505(12) u
[172.9252688 u]
{-30.2689 MeV}
(11/2-)
174Ir7717497Iridium-174173.966867(26) u
[173.9246308 u]
{-30.86319 MeV}
(3+)178Au
174mIr7717497Iridium-174m173.966867(26) u
[173.9246308 u]
{-30.86319 MeV}
(7+)
175Ir7717598Iridium-175174.964150(13) u
[174.9219138 u]
{-33.39406 MeV}
(5/2-)179Au
176Ir7717699Iridium-176175.963630(18) u
[175.9213938 u]
{-33.87844 MeV}
180Au
177Ir77177100Iridium-177176.961301(21) u
[176.9190648 u]
{-36.04789 MeV}
5/2-181Au
177Pt
178Ir77178101Iridium-178177.961082(21) u
[177.9188458 u]
{-36.25188 MeV}
182Au
178Pt
179Ir77179102Iridium-179178.959118(10) u
[178.9168818 u]
{-38.08134 MeV}
(5/2)-183Au
179Pt
180Ir77180103Iridium-180179.959229(23) u
[179.9169928 u]
{-37.97794 MeV}
(5+)184Au
180Pt
181Ir77181104Iridium-181180.957635(6) u
[180.9153988 u]
{-39.46274 MeV}
5/2-185Au
181Pt
182Ir77182105Iridium-182181.958076(23) u
[181.9158398 u]
{-39.05195 MeV}
3++ 2.6(2)182Pt
183Ir77183106Iridium-183182.956840(26) u
[182.9146038 u]
{-40.20328 MeV}
5/2-187Au
183Pt
184Ir77184107Iridium-184183.95748(3) u
[183.9152438 u]
{-39.60712 MeV}
5-+ 0.696(5)184Pt
184m1Ir77184107Iridium-184m1183.95748(3) u
[183.9152438 u]
{-39.60712 MeV}
3+
184m2Ir77184107Iridium-184m2183.95748(3) u
[183.9152438 u]
{-39.60712 MeV}
(7)+
185Ir77185108Iridium-185184.95670(3) u
[184.9144638 u]
{-40.33369 MeV}
5/2-+ 2.605(13)185Pt
186Ir77186109Iridium-186185.957947(18) u
[185.9157108 u]
{-39.17212 MeV}
5++ 3.88(5)186Pt
186mIr77186109Iridium-186m185.957947(18) u
[185.9157108 u]
{-39.17212 MeV}
2-0.638(8)
187Ir77187110Iridium-187186.95754(3) u
[186.9153038 u]
{-39.55124 MeV}
3/2++ 0.171(1)187Pt
187m1Ir77187110Iridium-187m1186.95754(3) u
[186.9153038 u]
{-39.55124 MeV}
9/2-
187m2Ir77187110Iridium-187m2186.95754(3) u
[186.9153038 u]
{-39.55124 MeV}
11/2-+.621(5)
188Ir77188111Iridium-188187.958835(10) u
[187.9165988 u]
{-38.34495 MeV}
1-+ 0.302(10)188Pt
189Ir77189112Iridium-189188.958723(13) u
[188.9164868 u]
{-38.44928 MeV}
3/2++0.147(7)189Pt
189m1Ir77189112Iridium-189m1188.958723(13) u
[188.9164868 u]
{-38.44928 MeV}
11/2-
189m2Ir77189112Iridium-189m2188.958723(13) u
[188.9164868 u]
{-38.44928 MeV}
(25/2)+
190Ir77190113Iridium-190189.9605434(15) u
[189.9183072 u]
{-36.75359 MeV}
4-0.04(1)
190m1Ir77190113Iridium-190m1189.9605434(15) u
[189.9183072 u]
{-36.75359 MeV}
(1-)
190m2Ir77190113Iridium-190m2189.9605434(15) u
[189.9183072 u]
{-36.75359 MeV}
(11)-
191Ir77191114Iridium-191190.96059(2) u
[190.9183538 u]
{-36.71018 MeV}
3/2++ 0.1507(6)191Os
191Pt
191m1Ir77191114Iridium-191m1190.96059(2) u
[190.9183538 u]
{-36.71018 MeV}
11/2-+ 6.03(4)
191m2Ir77191114Iridium-191m2190.96059(2) u
[190.9183538 u]
{-36.71018 MeV}
192Ir77192115Iridium-192191.9626025(14) u
[191.9203663 u]
{-34.83555 MeV}
4++1.924(10)
192m1Ir77192115Iridium-192m1191.9626025(14) u
[191.9203663 u]
{-34.83555 MeV}
1-
192m2Ir77192115Iridium-192m2191.9626025(14) u
[191.9203663 u]
{-34.83555 MeV}
(11-)
193Ir77193116Iridium-193192.96292(2) u
[192.9206838 u]
{-34.5398 MeV}
3/2++ 0.1637(6)193Os
193Pt
193mIr77193116Iridium-193m192.96292(2) u
[192.9206838 u]
{-34.5398 MeV}
11/2-
193m2Ir77193116Iridium-193m2192.96292(2) u
[192.9206838 u]
{-34.5398 MeV}
31/2+
194Ir77194117Iridium-194193.9650758(14) u
[193.9228396 u]
{-32.53168 MeV}
1-+ 0.39(1)194Os
194m1Ir77194117Iridium-194m1193.9650758(14) u
[193.9228396 u]
{-32.53168 MeV}
4+
194m2Ir77194117Iridium-194m2193.9650758(14) u
[193.9228396 u]
{-32.53168 MeV}
(10,11)
195Ir77195118Iridium-195194.9659770(14) u
[194.9237408 u]
{-31.69222 MeV}
3/2+
195mIr77195118Iridium-195m194.9659770(14) u
[194.9237408 u]
{-31.69222 MeV}
11/2-
196Ir77196119Iridium-196195.96840(4) u
[195.9261638 u]
{-29.43521 MeV}
(0-)196Os
196mIr77196119Iridium-196m195.96840(4) u
[195.9261638 u]
{-29.43521 MeV}
(10,11-)
197Ir77197120Iridium-197196.969657(22) u
[196.9274208 u]
{-28.26432 MeV}
3/2+
197mIr77197120Iridium-197m196.969657(22) u
[196.9274208 u]
{-28.26432 MeV}
11/2-
198Ir77198121Iridium-198197.97228(21) u
[197.9300438 u]
{-25.82101 MeV}
199Ir77199122Iridium-199198.97381(4) u
[198.9315738 u]
{-24.39583 MeV}
200Ir77200123Iridium-200199.97680(21) u
[199.9345638 u]
{-21.61066 MeV}
201Ir77201124Iridium-201200.97864(21) u
[200.9364038 u]
{-19.89671 MeV}
202Ir77202125Iridium-202201.98199(32) u
[201.9397538 u]
{-16.77621 MeV}
(1-,2-)
203Ir77203126Iridium-203202.98423(43) u
[202.9419938 u]
{-14.68966 MeV}
204Ir77204127Iridium-204203.98960(43) u
[203.9473638 u]
{-9.68754 MeV}
205Ir77205128Iridium-205204.99360(54) u
[204.9513638 u]
{-5.96156 MeV}

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
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) %

180(50) keV
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) %

172(6) keV
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) %


175.3(22) keV
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) %


+x keV
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) %
?
?


153(24) keV
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) %
?
?


+x keV
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) %
?
?


+x keV
Ir-1724.4(3) sα → 168Re
EC/β+172Os
ca. 2 %
ca. 98 %
5.991(10)MeV
9.86(3) MeV
+x keVAL
Ir-172m2.19(7) sα → 168Re
EC/β+172Os
9.5(11) %
90.5(11) %

139(10) keV
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) %

226(18) keV
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) %

193(11) keV
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 %225.65(11) keV
Ir-184m2350(90) ns328.40(24) keV
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 %

+x keV
Ir-18710.5(3) hEC/β+187Os100 %1.670(28) MeVAL
Ir-187m130.3(6) msIso → 187Ir100 %186.16(4) keV
Ir-187m2152(12) ns433.75(6) keV
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 %372.17(4) keV
Ir-189m23.7(2) msIso → 189Ir100 %2333.2(5) keV
Ir-19011.78(10)dEC → 190Os
β+190Os
> 99.99 %
< 0.002 %
1.9542(15) MeV
AL
Ir-190m11.120(3) hIso → 190Ir100 %26.1(1) keV
Ir-190m23.087(12) hIso → 190Ir
EC/β+190Os
8.6(2) %
91.4(2) %

376.4(1) keV
Ir-191stableAL
Ir-191m14.899(23) sIso → 191Ir100 %171.29(4) keV
Ir-191m25.5(7) sIso → 191Ir100 %2046.7+x keV
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 %

56.720(5) keV
Ir-192m2241(9) aIso → 192Ir100 %168.14(12) keV
Ir-193stableAL
Ir-193m10.53(4) dIso → 193Ir100 %80.239(6) keV
Ir-193m2124.8(21) μsIso → 193Ir100 %2278.9(5) keV
Ir-19419.28(13) hβ-194Pt100 %2.2284(13) MeVAL
Ir-194m131.85(24) msIso → 194Ir100 %147.072(2) keV
Ir-194m2171(11) dβ-194Pt100 %190+x keV
Ir-1952.29(17) hβ-195Pt100 %1.1016(13) MeVAL
Ir-195m3.67(82) hβ-195Pt
Iso → 195Ir
95(5) %
5(5) %

100(5) keV
Ir-19652(1) sβ-196Pt100 %3.21(4) MeVAL
Ir-196m1.40(2) hβ-196Pt
Iso → 196Ir
> 99.7 %
< 0.3 %

410(11) keV
Ir-1975.8(5) minβ-197Pt100 %2.156(20) MeVAL
Ir-197m8.9(3) minβ-197Pt
Iso → 197Ir
99.75(10) %
0.25(10) %

115(5) keV
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 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Iridium isotope.
6 - 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.
7 - Nuclear spin I, unit: h/2π.
8 - Nuclear magnetic moment μmag.
9 - 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.
10 - Decay: Half-live of the Iridium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
11 - Decay: 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.
12 - Decay percentage in percent (%).
13 - Decay energy; Particle energy related to decay type.
14 - AE = Excitation energy for metastable nuclei.
15 - 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
107 rad T-1 s-1
Quadrupole
moment
Q fm-2
Resonant
frequency
v0 bei 1 T
Relative
sensitivity
H0 = const.
v0 = const. 2)
191Ir
37,3(2) %
3/2+
+ 0,1507(6)0,4665+ 81,6(9)0,76580,00003
0,0899
193Ir
62,7(2) %
3/2+
+ 0,1637(6)0,508+ 75,1(9)0,83190,00004
0,0977

1) Quantity Percentage of natural occurrence.

2) 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), DOI https://www.ingentaconnect.com/content/matthey/pmr/2003/00000047/00000004/art00005.

[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.

 


Category: Isotopes

Last update: 05.07.2020



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