Promethium-157
Properties and data of the isotope 157Pm.
See also: List of individual Promethium isotopes (and general data sources).
General data
Name of the isotope:Promethium-157; Pm-157Symbol:157Pm or 15761PmMass number A:157 (= number of nucleons)Atomic number Z:61 (= number of protons)Neutrons N:96Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.5737704918033 (= neutron-proton ratio)Neutron excess (N-Z):35Isotopic mass:156.933121(8) u (atomic weight of Promethium-157)Nuclide mass:156.8996602 u (calculated nuclear mass without electrons)Mass excess:-62.29739 MeVMass defect:1.376037888 u (per nucleus)Nuclear binding energy:1281.77103644 MeV (per nucleus)
8.16414673 MeV (average binding energy per nucleon)Separation energy:SN = 6.205(8) MeV (first neutron)
SP = 9.11(20) MeV (first proton)Half-life:10.56(10) sDecay constant λ:0.065638937553025 s-1Specific activity α:2.533890563082 × 10+20 Bq g-1
6848352873.1965 Ci g-1Spin and parity:
(nuclear angular momentum)(5/2-)Year of discovery:1987
Radioactive Decay
Half-life T½ = 10.56(10) s respectively 1.056 × 101 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| β- | 157Sm | 100 % | 4.381(8) MeV | |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 96) and isobaric (same nucleon number A = 157) with Promethium-157. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 96 | Isobar A = 157 |
|---|
| 55 | 151Cs | |
| 56 | 152Ba | |
| 57 | 153La | |
| 58 | 154Ce | 157Ce |
| 59 | 155Pr | 157Pr |
| 60 | 156Nd | 157Nd |
| 61 | 157Pm | 157Pm |
| 62 | 158Sm | 157Sm |
| 63 | 159Eu | 157Eu |
| 64 | 160Gd | 157Gd |
| 65 | 161Tb | 157Tb |
| 66 | 162Dy | 157Dy |
| 67 | 163Ho | 157Ho |
| 68 | 164Er | 157Er |
| 69 | 165Tm | 157Tm |
| 70 | 166Yb | 157Yb |
| 71 | 167Lu | 157Lu |
| 72 | 168Hf | 157Hf |
| 73 | 169Ta | 157Ta |
| 74 | 170W | 157W |
| 75 | 171Re | |
| 76 | 172Os | |
| 77 | 173Ir | |
| 78 | 174Pt | |
| 79 | 175Au | |
| 80 | 176Hg | |
| 81 | 177Tl | |
| 82 | 178Pb | |
External data and identifiers
Last update: 2020-10-20
Perma link: https://www.chemlin.org/isotope/promethium-157
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