Iodine-129

Iodine-129
General
Symbol129I
Namesiodine-129
Protons (Z)53
Neutrons (N)76
Nuclide data
Natural abundanceTrace
Half-life (t1/2)1.614(12)×107 years
Isotope mass128.9049836(34) Da
Decay products129Xe
Decay modes
Decay modeDecay energy (MeV)
β0.189
Isotopes of iodine
Complete table of nuclides

Iodine-129 (129I) is a long-lived radioisotope of iodine that occurs naturally but is also of special interest in the monitoring and effects of man-made nuclear fission products, where it serves as both a tracer and a potential radiological contaminant.