Europium-139
Properties and data of the isotope 139Eu.
See also: list of Europium isotopes.
General data
Name of the isotope:Europium-139; Eu-139Symbol:139Eu or 13963EuMass number A:139 (= number of nucleons)Atomic number Z:63 (= number of protons)Neutrons N:76Isotopic mass:138.929792(14) u (atomic weight of Europium-139)Nuclide mass:138.8952342 u (calculated nuclear mass without electrons)Mass excess:-65.39833 MeVMass defect:1.221718632 u (per nucleus)Nuclear binding energy:1138.0235754 MeV (per nucleus)
8.18721997 MeV (average binding energy per nucleon)Separation energy:SN = 11.72(3) MeV (first neutron)
SP = 1.189(18) MeV (first proton)Half-life:17.9(6) sDecay constant λ:0.038723306176533 s-1Specific activity α:1.689834814185 × 10+20 Bq g-1
4567121119.4192 Ci g-1Spin and parity:
(nuclear angular momentum)(11/2)-Magnetic dipole moment:μ(μN) = 6.1(8)Nuclear g-factor:gl = 1.1090909090909Charge radius:4.9760(92) femtometer fmYear of discovery:1975
Radioactive Decay
Half-life T½ = 17.9(6) s respectively 1.79 × 101 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
EC/β+ | 139Sm | 100 % | 6.982(17) MeV | |
Parent Nuclides
Direct parent isotope is: 139Gd.
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 |
---|
139mEu | 148.3(3) keV | 10(2) μs | (7/2+) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 76) and isobaric (same nucleon number A = 139) with Europium-139. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
Z | Isotone N = 76 | Isobar A = 139 |
42 | 118Mo | |
43 | 119Tc | |
44 | 120Ru | |
45 | 121Rh | |
46 | 122Pd | |
47 | 123Ag | |
48 | 124Cd | |
49 | 125In | |
50 | 126Sn | 139Sn |
51 | 127Sb | 139Sb |
52 | 128Te | 139Te |
53 | 129I | 139I |
54 | 130Xe | 139Xe |
55 | 131Cs | 139Cs |
56 | 132Ba | 139Ba |
57 | 133La | 139La |
58 | 134Ce | 139Ce |
59 | 135Pr | 139Pr |
60 | 136Nd | 139Nd |
61 | 137Pm | 139Pm |
62 | 138Sm | 139Sm |
63 | 139Eu | 139Eu |
64 | 140Gd | 139Gd |
65 | 141Tb | 139Tb |
66 | 142Dy | 139Dy |
67 | 143Ho | |
68 | 144Er | |
69 | 145Tm | |
External data and identifiers
Last update: 2020-10-20
Perma link: https://www.chemlin.org/isotope/europium-139
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