Xenon-127m
Properties and data of the isotope 127mXe.
See also: List of individual Xenon isotopes (and general data sources).
General data
Name of the isotope:Xenon-127m; Xe-127mSymbol:127mXe or 127m54XeMass number A:127 (= number of nucleons)Atomic number Z:54 (= number of protons)Neutrons N:73Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.3518518518519 (= neutron-proton ratio)Neutron excess (N-Z):19Excitation energy:297.10(8) keVIsotopic mass:126.905184(4) u (atomic weight of Xenon-127m)Nuclide mass:126.8755626 u (calculated nuclear mass without electrons)Mass excess:-88.32054 MeVMass defect:1.149906596 u (per nucleus)Nuclear binding energy:1071.13109473 MeV (per nucleus)
8.43410311 MeV (average binding energy per nucleon)Half-life:69.2(9) sDecay constant λ:0.010016577753756 s-1Specific activity α:4.787400172034 × 10+19 Bq g-1
1293891938.3876 Ci g-1Spin and parity:
(nuclear angular momentum)9/2-Magnetic dipole moment:μ(μN) = -0.8844(10)Nuclear g-factor:gl = -0.19653333333333
Radioactive Decay
Half-life T½ = 69.2(9) s respectively 6.92 × 101 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| Iso | 127Xe | 100 % | 0.2971(8) MeV | 0.1246(3) MeV [69(3) %]
0.1725(3) MeV [38(3) %] |
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 |
|---|
| 127Xe | | 36.346(3) d | 1/2+ |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 73) and isobaric (same nucleon number A = 127) with Xenon-127m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 73 | Isobar A = 127 |
|---|
| 41 | 114Nb | |
| 42 | 115Mo | |
| 43 | 116Tc | |
| 44 | 117Ru | |
| 45 | 118Rh | 127Rh |
| 46 | 119Pd | 127Pd |
| 47 | 120Ag | 127Ag |
| 48 | 121Cd | 127Cd |
| 49 | 122In | 127In |
| 50 | 123Sn | 127Sn |
| 51 | 124Sb | 127Sb |
| 52 | 125Te | 127Te |
| 53 | 126I | 127I |
| 54 | 127Xe | 127Xe |
| 55 | 128Cs | 127Cs |
| 56 | 129Ba | 127Ba |
| 57 | 130La | 127La |
| 58 | 131Ce | 127Ce |
| 59 | 132Pr | 127Pr |
| 60 | 133Nd | 127Nd |
| 61 | 134Pm | 127Pm |
| 62 | 135Sm | |
| 63 | 136Eu | |
| 64 | 137Gd | |
| 65 | 138Tb | |
| 66 | 139Dy | |
| 67 | 140Ho | |
External data and identifiers
Last update: 2023-05-22
Perma link: https://www.chemlin.org/isotope/xenon-127m
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