Iridium-189
Properties and data of the isotope 189Ir.
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-1Spin 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 | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
EC | 189Os | 100 % | 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 Isomer | Excitation Energy | Half-life | Spin |
---|
189m1Ir | 372.17(4) keV | 13.3(3) ms | 11/2- |
189m2Ir | 2333.2(5) keV | 3.7(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.
Z | Isotone N = 112 | Isobar A = 189 |
70 | 182Yb | |
71 | 183Lu | |
72 | 184Hf | 189Hf |
73 | 185Ta | 189Ta |
74 | 186W | 189W |
75 | 187Re | 189Re |
76 | 188Os | 189Os |
77 | 189Ir | 189Ir |
78 | 190Pt | 189Pt |
79 | 191Au | 189Au |
80 | 192Hg | 189Hg |
81 | 193Tl | 189Tl |
82 | 194Pb | 189Pb |
83 | 195Bi | 189Bi |
84 | 196Po | 189Po |
85 | 197At | |
86 | 198Rn | |
87 | 199Fr | |
External data and identifiers
CAS:14265-84-0InChI Key:GKOZUEZYRPOHIO-OIOBTWANSA-NSMILES:[189Ir]PubChem:ID 178177Adopted Levels, Gammas:NuDat 189Ir
Last update: 2024-09-06
Perma link: https://www.chemlin.org/isotope/iridium-189
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