Promethium-137
Properties and data of the isotope 137Pm.
See also: list of Promethium isotopes.
General data
Name of the isotope:Promethium-137; Pm-137Symbol:137Pm or 13761PmMass number A:137 (= number of nucleons)Atomic number Z:61 (= number of protons)Neutrons N:76Isotopic mass:136.920480(14) u (atomic weight of Promethium-137)Nuclide mass:136.8870192 u (calculated nuclear mass without electrons)Mass excess:-74.0724 MeVMass defect:1.215380568 u (per nucleus)Nuclear binding energy:1132.11970681 MeV (per nucleus)
8.26364749 MeV (average binding energy per nucleon)Separation energy:SN = 10.97(7) MeV (first neutron)
SP = 2.163(18) MeV (first proton)Half-life:2.4(1) minDecay constant λ:0.0048135220872218 s-1Specific activity α:2.131449120710 × 10+19 Bq g-1
576067329.92184 Ci g-1Spin and parity:
(nuclear angular momentum)11/2-Year of discovery:1975
Radioactive Decay
Half-life T½ = 2.4(1) min (minutes) respectively 1.44 × 102 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
EC/β+ | 137Nd | 100 % | 5.512(18) MeV | |
Parent Nuclides
Direct parent isotope is: 137Sm.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 76) and isobaric (same nucleon number A = 137) with Promethium-137. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
Z | Isotone N = 76 | Isobar A = 137 |
42 | 118Mo | |
43 | 119Tc | |
44 | 120Ru | |
45 | 121Rh | |
46 | 122Pd | |
47 | 123Ag | |
48 | 124Cd | |
49 | 125In | 137In |
50 | 126Sn | 137Sn |
51 | 127Sb | 137Sb |
52 | 128Te | 137Te |
53 | 129I | 137I |
54 | 130Xe | 137Xe |
55 | 131Cs | 137Cs |
56 | 132Ba | 137Ba |
57 | 133La | 137La |
58 | 134Ce | 137Ce |
59 | 135Pr | 137Pr |
60 | 136Nd | 137Nd |
61 | 137Pm | 137Pm |
62 | 138Sm | 137Sm |
63 | 139Eu | 137Eu |
64 | 140Gd | 137Gd |
65 | 141Tb | 137Tb |
66 | 142Dy | |
67 | 143Ho | |
68 | 144Er | |
69 | 145Tm | |
External data and identifiers
Last update: 2020-10-20
Perma link: https://www.chemlin.org/isotope/promethium-137
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