Thulium-161
Properties and data of the isotope 161Tm.
See also: list of Thulium isotopes.
General data
Name of the isotope:Thulium-161; Tm-161Symbol:161Tm or 16169TmMass number A:161 (= number of nucleons)Atomic number Z:69 (= number of protons)Neutrons N:92Isotopic mass:160.93355(3) u (atomic weight of Thulium-161)Nuclide mass:160.8957014 u (calculated nuclear mass without electrons)Mass excess:-61.89778 MeVMass defect:1.40354948 u (per nucleus)Nuclear binding energy:1307.39791932 MeV (per nucleus)
8.12048397 MeV (average binding energy per nucleon)Separation energy:SN = 9.67(4) MeV (first neutron)
SP = 3.12(4) MeV (first proton)Half-life:30.2(8) minDecay constant λ:0.00038253155660041 s-1Specific activity α:1.439786823261 × 10+18 Bq g-1
38913157.385449 Ci g-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μN) = + 2.40(2)Quadrupole moment Q:+ 2.90(7) barn (100 fm2)Nuclear g-factor:gl = 0.68571428571429Charge radius:5.1616 (50) femtometer fmYear of discovery:1959
Radioactive Decay
Half-life T½ = 30.2(8) min (minutes) respectively 1.812 × 103 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| EC/β+ | 161Er | 100 % | 3.303(29) MeV | |
Parent Nuclides
Direct parent isotope is: 161Yb.
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 |
|---|
| 161mTm | 78.20(3) keV | 110(3) ns | 7/2- |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 92) and isobaric (same nucleon number A = 161) with Thulium-161. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 92 | Isobar A = 161 |
|---|
| 53 | 145I | |
| 54 | 146Xe | |
| 55 | 147Cs | |
| 56 | 148Ba | |
| 57 | 149La | |
| 58 | 150Ce | |
| 59 | 151Pr | |
| 60 | 152Nd | 161Nd |
| 61 | 153Pm | 161Pm |
| 62 | 154Sm | 161Sm |
| 63 | 155Eu | 161Eu |
| 64 | 156Gd | 161Gd |
| 65 | 157Tb | 161Tb |
| 66 | 158Dy | 161Dy |
| 67 | 159Ho | 161Ho |
| 68 | 160Er | 161Er |
| 69 | 161Tm | 161Tm |
| 70 | 162Yb | 161Yb |
| 71 | 163Lu | 161Lu |
| 72 | 164Hf | 161Hf |
| 73 | 165Ta | 161Ta |
| 74 | 166W | 161W |
| 75 | 167Re | 161Re |
| 76 | 168Os | 161Os |
| 77 | 169Ir | |
| 78 | 170Pt | |
| 79 | 171Au | |
| 80 | 172Hg | |
External data and identifiers
Last update: 2020-10-11
Perma link: https://www.chemlin.org/isotope/thulium-161
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