Iodine-129
Properties and data of the isotope 129I.
See also: List of individual Iodine isotopes (and general data sources).
General data
Name of the isotope:Iodine-129; I-129Other names:Jod-129Symbol:129I or 12953IMass number A:129 (= number of nucleons)Atomic number Z:53 (= number of protons)Neutrons N:76Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4339622641509 (= neutron-proton ratio)Neutron excess (N-Z):23Isotopic mass:128.904984(3) u (atomic weight of Iodine-129)Nuclide mass:128.8759111 u (calculated nuclear mass without electrons)Mass excess:-88.50683 MeVMass defect:1.168276312 u (per nucleus)Nuclear binding energy:1088.24237497 MeV (per nucleus)
8.4359874 MeV (average binding energy per nucleon)Separation energy:SN = 8.840(5) MeV (first neutron)
SP = 6.802(3) MeV (first proton)Half-life:1.57(4) × 107 aDecay constant λ:1.399971522910 × 10-15 s-1Specific activity α:6586582.5866132 Bq g-1
0.00017801574558414 Ci g-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μN) = +2.6165(14)Quadrupole moment Q:- 0.488(8) barn (100 fm2)Nuclear g-factor:gl = 0.74757142857143Year of discovery:1951
Radioactive Decay
Half-life T½ = 1.57(4) × 107 a respectively 4.951152 × 1014 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| β- | 129Xe | 100 % | 0.189(3) MeV | |
Parent Nuclides
Direct parent isotope is: 129Te.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 76) and isobaric (same nucleon number A = 129) with Iodine-129. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 76 | Isobar A = 129 |
|---|
| 42 | 118Mo | |
| 43 | 119Tc | |
| 44 | 120Ru | |
| 45 | 121Rh | |
| 46 | 122Pd | 129Pd |
| 47 | 123Ag | 129Ag |
| 48 | 124Cd | 129Cd |
| 49 | 125In | 129In |
| 50 | 126Sn | 129Sn |
| 51 | 127Sb | 129Sb |
| 52 | 128Te | 129Te |
| 53 | 129I | 129I |
| 54 | 130Xe | 129Xe |
| 55 | 131Cs | 129Cs |
| 56 | 132Ba | 129Ba |
| 57 | 133La | 129La |
| 58 | 134Ce | 129Ce |
| 59 | 135Pr | 129Pr |
| 60 | 136Nd | 129Nd |
| 61 | 137Pm | 129Pm |
| 62 | 138Sm | 129Sm |
| 63 | 139Eu | |
| 64 | 140Gd | |
| 65 | 141Tb | |
| 66 | 142Dy | |
| 67 | 143Ho | |
| 68 | 144Er | |
| 69 | 145Tm | |
External data and identifiers
Last update: 2020-10-18
Perma link: https://www.chemlin.org/isotope/iodine-129
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