Iridium-191
Properties and data of the isotope 191Ir.
See also: List of individual Iridium isotopes (and general data sources).
General data
Name of the isotope:Iridium-191; Ir-191Symbol:191Ir or 19177IrMass number A:191 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:114Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4805194805195 (= neutron-proton ratio)Neutron excess (N-Z):37Isotopic mass:190.96059(2) u (atomic weight of Iridium-191)Nuclide mass:190.9183538 u (calculated nuclear mass without electrons)Mass excess:-36.71018 MeVMass defect:1.629737888 u (per nucleus)Nuclear binding energy:1518.09106424 MeV (per nucleus)
7.94812076 MeV (average binding energy per nucleon)Separation energy:SN = 8.0265(4) MeV (first neutron)
SP = 5.2900(11) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μN) = + 0.1507(6)Charge radius:5.3968(1061) femtometer fmYear of discovery:1935
Parent Nuclides
Direct parent isotopes are: 191Os, 191Pt.
Occurrence
Comparison of the natural Iridium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
| | Atomic Mass ma | Quantity | Half-life | Spin |
|---|
Iridium
Isotopic mixture | 192.217 u | 100 % | | |
| Isotope 191Ir | 190.96059(2) u | 37.3(2) % | stable | 3/2+ |
| Isotope 193Ir | 192.96292(2) u | 62.7(2) % | stable | 3/2+ |
NMR data
Nuclear magnetic properties and parameters of the NMR active Nuclide 191Ir
Isotope:191Ir-NMRQuantity:37.3(2) %Spin:3/2+Nuclearmagnetic moment
μ/μN:+ 0.1507(6)Gyromagnetic ratio γ:0.4665 · 107 rad T-1 s-1
0.74246 MHz T-1Nuclear g-factor:gl = 0.10046666666667Quadrupole moment Q:+ 0.816(9) barn (100 fm2)Resonance frequency:v0 = 0.7658 MHz at 1 TRelative Sensitivity:[related to 1H = 1.000]:
0.00003 (H0 = const.)
0.0899 (v0 = const.)
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 |
|---|
| 191m1Ir | 171.29(4) keV | 4.899(23) s | 11/2- |
| 191m2Ir | 2046.7+x keV | 5.5(7) s | |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 114) and isobaric (same nucleon number A = 191) with Iridium-191. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 114 | Isobar A = 191 |
|---|
| 70 | 184Yb | |
| 71 | 185Lu | |
| 72 | 186Hf | |
| 73 | 187Ta | 191Ta |
| 74 | 188W | 191W |
| 75 | 189Re | 191Re |
| 76 | 190Os | 191Os |
| 77 | 191Ir | 191Ir |
| 78 | 192Pt | 191Pt |
| 79 | 193Au | 191Au |
| 80 | 194Hg | 191Hg |
| 81 | 195Tl | 191Tl |
| 82 | 196Pb | 191Pb |
| 83 | 197Bi | 191Bi |
| 84 | 198Po | 191Po |
| 85 | 199At | 191At |
| 86 | 200Rn | |
| 87 | 201Fr | |
| 88 | 202Ra | |
| 89 | 203Ac | |
External data and identifiers
Last update: 2020-10-21
Perma link: https://www.chemlin.org/isotope/iridium-191
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