Cesium-135
Properties and data of the isotope 135Cs.
See also: List of individual Cesium isotopes (and general data sources).
General data
Name of the isotope:Cesium-135; Cs-135Symbol:135Cs or 13555CsMass number A:135 (= number of nucleons)Atomic number Z:55 (= number of protons)Neutrons N:80Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4545454545455 (= neutron-proton ratio)Neutron excess (N-Z):25Isotopic mass:134.9059772(11) u (atomic weight of Cesium-135)Nuclide mass:134.8758073 u (calculated nuclear mass without electrons)Mass excess:-87.58167 MeVMass defect:1.21759284 u (per nucleus)Nuclear binding energy:1134.1804249 MeV (per nucleus)
8.40133648 MeV (average binding energy per nucleon)Separation energy:SN = 8.7618(10) MeV (first neutron)
SP = 6.7448(10) MeV (first proton)Half-life:2.3(3) × 106 aDecay constant λ:9.556327352038 × 10-15 s-1Specific activity α:42947424.938539 Bq g-1
0.0011607412145551 Ci g-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μN) = + 2.7283(13)Quadrupole moment Q:+0.050(2) barn (100 fm2)Nuclear g-factor:gl = 0.77951428571429Charge radius:4.8067(47) femtometer fmYear of discovery:1949
Radioactive Decay
Half-life T½ = 2.3(3) × 106 a respectively 7.25328 × 1013 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| β- | 135Ba | 100 % | 2.689(10) MeV | |
Parent Nuclides
Direct parent isotope is: 135Xe.
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 |
|---|
| 135mCs | 1632.9(15) keV | 53(2) min | 19/2- |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 80) and isobaric (same nucleon number A = 135) with Cesium-135. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 80 | Isobar A = 135 |
|---|
| 44 | 124Ru | |
| 45 | 125Rh | |
| 46 | 126Pd | |
| 47 | 127Ag | |
| 48 | 128Cd | |
| 49 | 129In | 135In |
| 50 | 130Sn | 135Sn |
| 51 | 131Sb | 135Sb |
| 52 | 132Te | 135Te |
| 53 | 133I | 135I |
| 54 | 134Xe | 135Xe |
| 55 | 135Cs | 135Cs |
| 56 | 136Ba | 135Ba |
| 57 | 137La | 135La |
| 58 | 138Ce | 135Ce |
| 59 | 139Pr | 135Pr |
| 60 | 140Nd | 135Nd |
| 61 | 141Pm | 135Pm |
| 62 | 142Sm | 135Sm |
| 63 | 143Eu | 135Eu |
| 64 | 144Gd | 135Gd |
| 65 | 145Tb | 135Tb |
| 66 | 146Dy | |
| 67 | 147Ho | |
| 68 | 148Er | |
| 69 | 149Tm | |
| 70 | 150Yb | |
| 71 | 151Lu | |
External data and identifiers
Last update: 2020-10-18
Perma link: https://www.chemlin.org/isotope/cesium-135
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