Lutetium-157m
Properties and data of the isotope 157mLu.
See also: List of individual Lutetium isotopes (and general data sources).
General data
Name of the isotope:Lutetium-157m; Lu-157mSymbol:157mLu or 157m71LuMass number A:157 (= number of nucleons)Atomic number Z:71 (= number of protons)Neutrons N:86Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.2112676056338 (= neutron-proton ratio)Neutron excess (N-Z):15Excitation energy:20.9(20) keVIsotopic mass:156.950144(13) u (atomic weight of Lutetium-157m)Nuclide mass:156.9111985 u (calculated nuclear mass without electrons)Mass excess:-46.44056 MeVMass defect:1.350616048 u (per nucleus)Nuclear binding energy:1258.09074502 MeV (per nucleus)
8.01331685 MeV (average binding energy per nucleon)Half-life:4.79(12) sDecay constant λ:0.14470713581627 s-1Specific activity α:5.586197149510 × 10+20 Bq g-1
15097830133.811 Ci g-1Spin and parity:
(nuclear angular momentum)(11/2-)
Radioactive Decay
Half-life T½ = 4.79(12) s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| α | 153Tm | 6(2) % | | |
| EC/β+ | 157Yb | 94(2) % | | |
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 |
|---|
| 157Lu | | 6.8(18) s | (1/2+,3/2+) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 86) and isobaric (same nucleon number A = 157) with Lutetium-157m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 86 | Isobar A = 157 |
|---|
| 48 | 134Cd | |
| 49 | 135In | |
| 50 | 136Sn | |
| 51 | 137Sb | |
| 52 | 138Te | |
| 53 | 139I | |
| 54 | 140Xe | |
| 55 | 141Cs | |
| 56 | 142Ba | |
| 57 | 143La | |
| 58 | 144Ce | 157Ce |
| 59 | 145Pr | 157Pr |
| 60 | 146Nd | 157Nd |
| 61 | 147Pm | 157Pm |
| 62 | 148Sm | 157Sm |
| 63 | 149Eu | 157Eu |
| 64 | 150Gd | 157Gd |
| 65 | 151Tb | 157Tb |
| 66 | 152Dy | 157Dy |
| 67 | 153Ho | 157Ho |
| 68 | 154Er | 157Er |
| 69 | 155Tm | 157Tm |
| 70 | 156Yb | 157Yb |
| 71 | 157Lu | 157Lu |
| 72 | 158Hf | 157Hf |
| 73 | 159Ta | 157Ta |
| 74 | 160W | 157W |
| 75 | 161Re | |
| 76 | 162Os | |
Last update: 2020-10-11
Perma link: https://www.chemlin.org/isotope/lutetium-157m
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