Lanthanum-137
Properties and data of the isotope 137La.
See also: List of individual Lanthanum isotopes (and general data sources).
General data
Name of the isotope:Lanthanum-137; La-137Symbol:137La or 13757LaMass number A:137 (= number of nucleons)Atomic number Z:57 (= number of protons)Neutrons N:80Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4035087719298 (= neutron-proton ratio)Neutron excess (N-Z):23Isotopic mass:136.9064506(18) u (atomic weight of Lanthanum-137)Nuclide mass:136.8751837 u (calculated nuclear mass without electrons)Mass excess:-87.1407 MeVMass defect:1.232769504 u (per nucleus)Nuclear binding energy:1148.31739636 MeV (per nucleus)
8.38187881 MeV (average binding energy per nucleon)Separation energy:SN = 9.17(5) MeV (first neutron)
SP = 5.5427(16) MeV (first proton)Half-life:60000 aDecay constant λ:3.663258818281 × 10-13 s-1Specific activity α:1622107397.8012 Bq g-1
0.043840740481114 Ci g-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μN) = +2.696(6)Quadrupole moment Q:+0.21(3) barn (100 fm2)Nuclear g-factor:gl = 0.77028571428571Charge radius:4.8496(53) femtometer fmYear of discovery:1948
Radioactive Decay
Half-life T½ = 60000 a respectively 1.89216 × 1012 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| EC | 137Ba | 100 % | 0.5805(17) MeV | |
Parent Nuclides
Direct parent isotope is: 137Ce.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 80) and isobaric (same nucleon number A = 137) with Lanthanum-137. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 80 | Isobar A = 137 |
|---|
| 44 | 124Ru | |
| 45 | 125Rh | |
| 46 | 126Pd | |
| 47 | 127Ag | |
| 48 | 128Cd | |
| 49 | 129In | 137In |
| 50 | 130Sn | 137Sn |
| 51 | 131Sb | 137Sb |
| 52 | 132Te | 137Te |
| 53 | 133I | 137I |
| 54 | 134Xe | 137Xe |
| 55 | 135Cs | 137Cs |
| 56 | 136Ba | 137Ba |
| 57 | 137La | 137La |
| 58 | 138Ce | 137Ce |
| 59 | 139Pr | 137Pr |
| 60 | 140Nd | 137Nd |
| 61 | 141Pm | 137Pm |
| 62 | 142Sm | 137Sm |
| 63 | 143Eu | 137Eu |
| 64 | 144Gd | 137Gd |
| 65 | 145Tb | 137Tb |
| 66 | 146Dy | |
| 67 | 147Ho | |
| 68 | 148Er | |
| 69 | 149Tm | |
| 70 | 150Yb | |
| 71 | 151Lu | |
External data and identifiers
Last update: 2020-10-19
Perma link: https://www.chemlin.org/isotope/lanthanum-137
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