Lanthanum-127m
Properties and data of the isotope 127mLa.
See also: list of Lanthanum isotopes.
General data
Name of the isotope:Lanthanum-127m; La-127mSymbol:127mLa or 127m57LaMass number A:127 (= number of nucleons)Atomic number Z:57 (= number of protons)Neutrons N:70Isotopic mass:126.916375(28) u (atomic weight of Lanthanum-127m)
Excitation energy: 14.2(4) keVNuclide mass:126.8851081 u (calculated nuclear mass without electrons)Mass excess:-77.89619 MeVMass defect:1.136195944 u (per nucleus)Nuclear binding energy:1058.35970466 MeV (per nucleus)
8.33354098 MeV (average binding energy per nucleon)Half-life:3.7(4) minDecay constant λ:0.0031222845971169 s-1Specific activity α:1.492288702273 × 10+19 Bq g-1
403321270.88478 Ci g-1Spin and parity:
(nuclear angular momentum)(3/2+)
Radioactive Decay
Half-life T½ = 3.7(4) min (minutes) respectively 2.22 × 102 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
EC/β+ | 127Ba | 100 % | | |
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 |
---|
127La | | 5.1(1) min | (11/2-) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 70) and isobaric (same nucleon number A = 127) with Lanthanum-127m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
Z | Isotone N = 70 | Isobar A = 127 |
39 | 109Y | |
40 | 110Zr | |
41 | 111Nb | |
42 | 112Mo | |
43 | 113Tc | |
44 | 114Ru | |
45 | 115Rh | 127Rh |
46 | 116Pd | 127Pd |
47 | 117Ag | 127Ag |
48 | 118Cd | 127Cd |
49 | 119In | 127In |
50 | 120Sn | 127Sn |
51 | 121Sb | 127Sb |
52 | 122Te | 127Te |
53 | 123I | 127I |
54 | 124Xe | 127Xe |
55 | 125Cs | 127Cs |
56 | 126Ba | 127Ba |
57 | 127La | 127La |
58 | 128Ce | 127Ce |
59 | 129Pr | 127Pr |
60 | 130Nd | 127Nd |
61 | 131Pm | 127Pm |
62 | 132Sm | |
63 | 133Eu | |
64 | 134Gd | |
65 | 135Tb | |
External data and identifiers
Last update: 2020-10-19
Perma link: https://www.chemlin.org/isotope/lanthanum-127m
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