Cesium-137
Properties and data of the isotope 137Cs.
See also: List of individual Cesium isotopes (and general data sources).
General data
Name of the isotope:Cesium-137; Cs-137Other names:Radiocäsium. Radiocaesium. Radiozäsium (veraltet)Symbol:137Cs or 13755CsMass number A:137 (= number of nucleons)Atomic number Z:55 (= number of protons)Neutrons N:82Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4909090909091 (= neutron-proton ratio)Neutron excess (N-Z):27Isotopic mass:136.9070893(3) u (atomic weight of Cesium-137)Nuclide mass:136.8769194 u (calculated nuclear mass without electrons)Mass excess:-86.54576 MeVMass defect:1.233810572 u (per nucleus)Nuclear binding energy:1149.28714495 MeV (per nucleus)
8.38895726 MeV (average binding energy per nucleon)Separation energy:SN = 8.2782(19) MeV (first neutron)
SP = 7.4054(4) MeV (first proton)Half-life:30.08(9) aDecay constant λ:7.307031292963 × 10-10 s-1Specific activity α:3235586155455.5 Bq g-1
87.44827447177 Ci g-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μN) = + 2.8374(14)Quadrupole moment Q:+0.051(1) barn (100 fm2)Nuclear g-factor:gl = 0.81068571428571Charge radius:4.8128(50) femtometer fmYear of discovery:1951
Radioactive Decay
Half-life T½ = 30.08(9) a respectively 9.48603 × 108 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| β- | 137Ba | 100 % | 1.17563(17) MeV | 661.657(3) keV
85.1(2) %
0.5631(13) MeV/Bq-s |
Parent Nuclides
Direct parent isotopes are: 137Xe, 252Cf.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 82) and isobaric (same nucleon number A = 137) with Cesium-137. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 82 | Isobar A = 137 |
|---|
| 45 | 127Rh | |
| 46 | 128Pd | |
| 47 | 129Ag | |
| 48 | 130Cd | |
| 49 | 131In | 137In |
| 50 | 132Sn | 137Sn |
| 51 | 133Sb | 137Sb |
| 52 | 134Te | 137Te |
| 53 | 135I | 137I |
| 54 | 136Xe | 137Xe |
| 55 | 137Cs | 137Cs |
| 56 | 138Ba | 137Ba |
| 57 | 139La | 137La |
| 58 | 140Ce | 137Ce |
| 59 | 141Pr | 137Pr |
| 60 | 142Nd | 137Nd |
| 61 | 143Pm | 137Pm |
| 62 | 144Sm | 137Sm |
| 63 | 145Eu | 137Eu |
| 64 | 146Gd | 137Gd |
| 65 | 147Tb | 137Tb |
| 66 | 148Dy | |
| 67 | 149Ho | |
| 68 | 150Er | |
| 69 | 151Tm | |
| 70 | 152Yb | |
| 71 | 153Lu | |
| 72 | 154Hf | |
| 73 | 155Ta | |
| 74 | 156W | |
External data and identifiers
CAS:10045-97-3InChI Key:TVFDJXOCXUVLDH-RNFDNDRNSA-NSMILES:[137Cs]PubChem:ID 5486527Adopted Levels, Gammas:NuDat 137Cs
Literature and References
[1] - NN:
Radiocäsium Kontamination & Lebensmittel.
In: Umweltanalysen, (2021).
[2] - NN:
Cäsiumfrei: Wilde Trüffel nicht radioaktiv belastet.
In: Internetchemie News, (2016).
Last update: 2023-09-27
Perma link: https://www.chemlin.org/isotope/cesium-137
© 1996 - 2026 ChemLin
