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Iridium-189

Properties and data of the isotope 189Ir.


Contents

 

Iridium-189 isotope

Iridium-189 is a radioisotope of the chemical element iridium, which has 112 neutrons in its atomic nucleus in addition to the element-specific 77 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 189. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of 189Ir is exclusively for academic purposes.

See also: list of Iridium isotopes.

 

General data

Name of the isotope:Iridium-189; Ir-189Symbol:189Ir or 18977IrMass number A:189 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:112Isotopic mass:188.958723(14) u (atomic weight of Iridium-189)Nuclide mass:188.9164868 u (calculated nuclear mass without electrons)Mass excess:-38.44928 MeVMass defect:1.614275056 u (per nucleus)Nuclear binding energy:1503.68752901 MeV (per nucleus)
7.95601867 MeV (average binding energy per nucleon)
Separation energy:SN = 8.176(16) MeV (first neutron)
SP = 4.601(13) MeV (first proton)
Half-life:13.2(1) dDecay constant λ:6.077679403057 × 10-7 s-1Specific activity α:1.946842631210 × 10+15 Bq g-1
52617.368411086 Ci g-1
Spin and parity:
(nuclear angular momentum)
3/2+Magnetic dipole moment:μ(μN) = +0.147(7)Quadrupole moment Q:+ 0.828(8) barn (100 fm2)Nuclear g-factor:gl = 0.098Charge radius:5.3898(1061) femtometer fmYear of discovery:1955

 

Radioactive Decay

Half-life T½ = 13.2(1) d respectively 1.140480 × 106 seconds s.

Decay
mode
DaughterProbabilityDecay energyγ energy
(intensity)
EC189Os100 %0.537(13) MeV

 

Parent Nuclides

Direct parent isotope is: 189Pt.

 

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear IsomerExcitation EnergyHalf-lifeSpin
189m1Ir372.17(4) keV13.3(3) ms11/2-
189m2Ir2333.2(5) keV3.7(2) ms(25/2)+

 

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 112) and isobaric (same nucleon number A = 189) with Iridium-189. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

 

ZIsotone N = 112Isobar A = 189
70182Yb
71183Lu
72184Hf189Hf
73185Ta189Ta
74186W189W
75187Re189Re
76188Os189Os
77189Ir189Ir
78190Pt189Pt
79191Au189Au
80192Hg189Hg
81193Tl189Tl
82194Pb189Pb
83195Bi189Bi
84196Po189Po
85197At
86198Rn
87199Fr

 

External data and identifiers

CAS:14265-84-0InChI Key:GKOZUEZYRPOHIO-OIOBTWANSA-NSMILES:[189Ir]PubChem:ID 178177Adopted Levels, Gammas:NuDat 189Ir

 


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Last update: 2024-09-06


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