Xenon-135m
Properties and data of the isotope 135mXe.
See also: List of individual Xenon isotopes (and general data sources).
General data
Name of the isotope:Xenon-135m; Xe-135mSymbol:135mXe or 135m54XeMass number A:135 (= number of nucleons)Atomic number Z:54 (= number of protons)Neutrons N:81Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5 (= neutron-proton ratio)Neutron excess (N-Z):27Excitation energy:526.551(13) keVIsotopic mass:134.907232(4) u (atomic weight of Xenon-135m)Nuclide mass:134.8776106 u (calculated nuclear mass without electrons)Mass excess:-86.41284 MeVMass defect:1.217177924 u (per nucleus)Nuclear binding energy:1133.79393314 MeV (per nucleus)
8.39847358 MeV (average binding energy per nucleon)Half-life:15.29(5) minDecay constant λ:0.00075555611571827 s-1Specific activity α:3.39557116152 × 10+18 Bq g-1
91772193.554703 Ci g-1Spin and parity:
(nuclear angular momentum)11/2-Magnetic dipole moment:μ(μN) = - 1.1036(14)Quadrupole moment Q:0.618(21) barn (100 fm2)Nuclear g-factor:gl = -0.20065454545455
Radioactive Decay
Half-life T½ = 15.29(5) min (minutes) respectively 9.174 × 102 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| Iso | 135Xe | > 99.4 % | | |
| β- | 135Cs | < 0.6 % | | |
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 |
|---|
| 135Xe | | 9.14(2) h | 3/2+ |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 81) and isobaric (same nucleon number A = 135) with Xenon-135m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 81 | Isobar A = 135 |
|---|
| 45 | 126Rh | |
| 46 | 127Pd | |
| 47 | 128Ag | |
| 48 | 129Cd | |
| 49 | 130In | 135In |
| 50 | 131Sn | 135Sn |
| 51 | 132Sb | 135Sb |
| 52 | 133Te | 135Te |
| 53 | 134I | 135I |
| 54 | 135Xe | 135Xe |
| 55 | 136Cs | 135Cs |
| 56 | 137Ba | 135Ba |
| 57 | 138La | 135La |
| 58 | 139Ce | 135Ce |
| 59 | 140Pr | 135Pr |
| 60 | 141Nd | 135Nd |
| 61 | 142Pm | 135Pm |
| 62 | 143Sm | 135Sm |
| 63 | 144Eu | 135Eu |
| 64 | 145Gd | 135Gd |
| 65 | 146Tb | 135Tb |
| 66 | 147Dy | |
| 67 | 148Ho | |
| 68 | 149Er | |
| 69 | 150Tm | |
| 70 | 151Yb | |
| 71 | 152Lu | |
| 72 | 153Hf | |
External data and identifiers
Last update: 2020-10-18
Perma link: https://www.chemlin.org/isotope/xenon-135m
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