Iodine-131
Properties and data of the isotope 131I.
See also: list of Iodine isotopes.
General data
Name of the isotope:Iodine-131; I-131Other names:Radioiod. Jod-131Symbol:131I or 13153IMass number A:131 (= number of nucleons)Atomic number Z:53 (= number of protons)Neutrons N:78Isotopic mass:130.9061264(6) u (atomic weight of Iodine-131)Nuclide mass:130.8770535 u (calculated nuclear mass without electrons)Mass excess:-87.4427 MeVMass defect:1.184463744 u (per nucleus)Nuclear binding energy:1103.32087075 MeV (per nucleus)
8.42229672 MeV (average binding energy per nucleon)Separation energy:SN = 8.578(3) MeV (first neutron)
SP = 7.3787(6) MeV (first proton)Half-life:8.0252(6) dDecay constant λ:9.9966814684 × 10-7 s-1Specific activity α:4.630878764211 × 10+15 Bq g-1
125158.88551922 Ci g-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μN) = + 2.738(1)Quadrupole moment Q:- 0.35(2) barn (100 fm2)Nuclear g-factor:gl = 0.78228571428571Year of discovery:1938
Radioactive Decay
Half-life T½ = 8.0252(6) d respectively 6.9337728 × 105 seconds s.
Decay mode | Daughter | Probability | Decay energy | γ energy (intensity) |
---|
β- | 131Xe | 100 % | 0.9708(6) MeV | 364.489(5) MeV 81.5(8) % |
Parent Nuclides
Direct parent isotope is: 131Te.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 78) and isobaric (same nucleon number A = 131) with Iodine-131. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
OZ | Isotone N = 78 | Isobar A = 131 |
43 | 121Tc | |
44 | 122Ru | |
45 | 123Rh | |
46 | 124Pd | |
47 | 125Ag | 131Ag |
48 | 126Cd | 131Cd |
49 | 127In | 131In |
50 | 128Sn | 131Sn |
51 | 129Sb | 131Sb |
52 | 130Te | 131Te |
53 | 131I | 131I |
54 | 132Xe | 131Xe |
55 | 133Cs | 131Cs |
56 | 134Ba | 131Ba |
57 | 135La | 131La |
58 | 136Ce | 131Ce |
59 | 137Pr | 131Pr |
60 | 138Nd | 131Nd |
61 | 139Pm | 131Pm |
62 | 140Sm | 131Sm |
63 | 141Eu | 131Eu |
64 | 142Gd | |
65 | 143Tb | |
66 | 144Dy | |
67 | 145Ho | |
68 | 146Er | |
69 | 147Tm | |
70 | 148Yb | |
71 | 149Lu | |
External data and identifiers
Last update: 2023-05-22
Perma link: https://www.chemlin.org/isotope/iodine-131
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