Promethium-135
Properties and data of the isotope 135Pm.
See also: List of individual Promethium isotopes (and general data sources).
General data
Name of the isotope:Promethium-135; Pm-135Symbol:135Pm or 13561PmMass number A:135 (= number of nucleons)Atomic number Z:61 (= number of protons)Neutrons N:74Isotopic mass:134.92480(8) u (atomic weight of Promethium-135)Nuclide mass:134.8913392 u (calculated nuclear mass without electrons)Mass excess:-70.04835 MeVMass defect:1.193730736 u (per nucleus)Nuclear binding energy:1111.9530182 MeV (per nucleus)
8.23668902 MeV (average binding energy per nucleon)Separation energy:SN = 11.38(19) MeV (first neutron)
SP = 1.69(8) MeV (first proton)Half-life:49(3) sDecay constant λ:0.014145860827754 s-1Specific activity α:6.357340782820 × 10+19 Bq g-1
1718200211.5731 Ci g-1Spin and parity:
(nuclear angular momentum)(5/2+.3/2+)Year of discovery:1975
Radioactive Decay
Half-life T½ = 49(3) s respectively 4.9 × 101 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| EC/β+ | 135Nd | 100 % | 6.616(8) MeV | |
Parent Nuclides
Direct parent isotopes are: 135Sm, 136Eu.
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 |
|---|
| 135mPm | 68.7+y keV | 45(4) s | (11/2-) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 74) and isobaric (same nucleon number A = 135) with Promethium-135. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 74 | Isobar A = 135 |
|---|
| 41 | 115Nb | |
| 42 | 116Mo | |
| 43 | 117Tc | |
| 44 | 118Ru | |
| 45 | 119Rh | |
| 46 | 120Pd | |
| 47 | 121Ag | |
| 48 | 122Cd | |
| 49 | 123In | 135In |
| 50 | 124Sn | 135Sn |
| 51 | 125Sb | 135Sb |
| 52 | 126Te | 135Te |
| 53 | 127I | 135I |
| 54 | 128Xe | 135Xe |
| 55 | 129Cs | 135Cs |
| 56 | 130Ba | 135Ba |
| 57 | 131La | 135La |
| 58 | 132Ce | 135Ce |
| 59 | 133Pr | 135Pr |
| 60 | 134Nd | 135Nd |
| 61 | 135Pm | 135Pm |
| 62 | 136Sm | 135Sm |
| 63 | 137Eu | 135Eu |
| 64 | 138Gd | 135Gd |
| 65 | 139Tb | 135Tb |
| 66 | 140Dy | |
| 67 | 141Ho | |
External data and identifiers
Last update: 2020-10-20
Perma link: https://www.chemlin.org/isotope/promethium-135
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