Iridium-172
Properties and data of the isotope 172Ir.
See also: List of individual Iridium isotopes (and general data sources).
General data
Name of the isotope:Iridium-172; Ir-172Symbol:172Ir or 17277IrMass number A:172 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:95Isotopic mass:171.97061(3) u (atomic weight of Iridium-172)
Excitation energy: +x keVNuclide mass:171.9283738 u (calculated nuclear mass without electrons)Mass excess:-27.37661 MeVMass defect:1.455084484 u (per nucleus)Nuclear binding energy:1355.40246634 MeV (per nucleus)
7.8802469 MeV (average binding energy per nucleon)Separation energy:SN = 9.04(5) MeV (first neutron)
SP = 0.37(4) MeV (first proton)Half-life:4.4(3) sDecay constant λ:0.15753345012726 s-1Specific activity α:5.547886706539 × 10+20 Bq g-1
14994288396.052 Ci g-1Spin and parity:
(nuclear angular momentum)(3-.4-)Year of discovery:1967
Radioactive Decay
Half-life T½ = 4.4(3) s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| α | 168Re | ca. 2 % | 5.991(10)MeV | |
| EC/β+ | 172Os | ca. 98 % | 9.86(3) MeV | |
Parent Nuclides
Direct parent isotope is: 176Au.
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 |
|---|
| 172mIr | 139(10) keV | 2.19(7) s | (7+) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 95) and isobaric (same nucleon number A = 172) with Iridium-172. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 95 | Isobar A = 172 |
|---|
| 55 | 150Cs | |
| 56 | 151Ba | |
| 57 | 152La | |
| 58 | 153Ce | |
| 59 | 154Pr | |
| 60 | 155Nd | |
| 61 | 156Pm | |
| 62 | 157Sm | |
| 63 | 158Eu | |
| 64 | 159Gd | |
| 65 | 160Tb | 172Tb |
| 66 | 161Dy | 172Dy |
| 67 | 162Ho | 172Ho |
| 68 | 163Er | 172Er |
| 69 | 164Tm | 172Tm |
| 70 | 165Yb | 172Yb |
| 71 | 166Lu | 172Lu |
| 72 | 167Hf | 172Hf |
| 73 | 168Ta | 172Ta |
| 74 | 169W | 172W |
| 75 | 170Re | 172Re |
| 76 | 171Os | 172Os |
| 77 | 172Ir | 172Ir |
| 78 | 173Pt | 172Pt |
| 79 | 174Au | 172Au |
| 80 | 175Hg | 172Hg |
| 81 | 176Tl | |
External data and identifiers
Last update: 2020-10-21
Perma link: https://www.chemlin.org/isotope/iridium-172
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