Iodine-126

Properties and data of the isotope ¹²⁶I.

Content

General data

Name of the isotope:Iodine-126; I-126Other names:Jod-126Symbol:¹²⁶I or 12653IMass number A:126 (= number of nucleons)Atomic number Z:53 (= number of protons)Neutrons N:73Isotopic mass:125.905623(4) u (atomic weight of Iodine-126)Nuclide mass:125.8765501 u (calculated nuclear mass without electrons)Mass excess:-87.91161 MeVMass defect:1.141642564 u (per nucleus)Nuclear binding energy:1063.43319851 MeV (per nucleus)
8.43994602 MeV (average binding energy per nucleon)Separation energy:S_N = 7.145(4) MeV (first neutron)
S_P = 6.177(4) MeV (first proton)Half-life:12.93(5) dDecay constant λ:6.204591501961 × 10^-7 s^-1Specific activity α:2.989193920254 × 10⁺¹⁵ Bq g^-1
80789.024871741 Ci g^-1Spin and parity:
(nuclear angular momentum)2-Magnetic dipole moment:μ(μ_N) = 1.438(4)Nuclear g-factor:g_l = 0.719Year of discovery:1938

Radioactive Decay

Half-life T_½ = 12.93(5) d respectively 1.117152 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹²⁶Te	52.7(5) %	2.154(4) MeV
β^-	¹²⁶Xe	44.3(5) %	1.236(5) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 73) and isobaric (same nucleon number A = 126) with Iodine-126. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 73	Isobar A = 126
41	¹¹⁴Nb
42	¹¹⁵Mo
43	¹¹⁶Tc
44	¹¹⁷Ru
45	¹¹⁸Rh	¹²⁶Rh
46	¹¹⁹Pd	¹²⁶Pd
47	¹²⁰Ag	¹²⁶Ag
48	¹²¹Cd	¹²⁶Cd
49	¹²²In	¹²⁶In
50	¹²³Sn	¹²⁶Sn
51	¹²⁴Sb	¹²⁶Sb
52	¹²⁵Te	¹²⁶Te
53	¹²⁶I	¹²⁶I
54	¹²⁷Xe	¹²⁶Xe
55	¹²⁸Cs	¹²⁶Cs
56	¹²⁹Ba	¹²⁶Ba
57	¹³⁰La	¹²⁶La
58	¹³¹Ce	¹²⁶Ce
59	¹³²Pr	¹²⁶Pr
60	¹³³Nd	¹²⁶Nd
61	¹³⁴Pm	¹²⁶Pm
62	¹³⁵Sm
63	¹³⁶Eu
64	¹³⁷Gd
65	¹³⁸Tb
66	¹³⁹Dy
67	¹⁴⁰Ho