Iodine-125

Properties and data of the isotope ¹²⁵I.

Content

General data

Name of the isotope:Iodine-125; I-125Other names:Jod-125Symbol:¹²⁵I or 12553IMass number A:125 (= number of nucleons)Atomic number Z:53 (= number of protons)Neutrons N:72Isotopic mass:124.9046306(15) u (atomic weight of Iodine-125)Nuclide mass:124.8755577 u (calculated nuclear mass without electrons)Mass excess:-88.83602 MeVMass defect:1.133970048 u (per nucleus)Nuclear binding energy:1056.28629589 MeV (per nucleus)
8.45029037 MeV (average binding energy per nucleon)Separation energy:S_N = 9.5428(19) MeV (first neutron)
S_P = 5.60085(7) MeV (first proton)Half-life:59.407(10) dDecay constant λ:1.350436280579 × 10^-7 s^-1Specific activity α:6.558481858077 × 10⁺¹⁴ Bq g^-1
17725.626643454 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2+Magnetic dipole moment:μ(μ_N) = 2.821(5)Quadrupole moment Q:- 0.776(17) barn (100 fm²)Nuclear g-factor:g_l = 1.1284Year of discovery:1947

Radioactive Decay

Half-life T_½ = 59.407(10) d respectively 5.1327648 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE	¹²⁵Te	100 %	0.1858(21) MeV	35.4925(5) keV 6.68(13) %

Parent Nuclides

Direct parent isotope is: ¹²⁵Xe.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 72) and isobaric (same nucleon number A = 125) with Iodine-125. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 72	Isobar A = 125
40	¹¹²Zr
41	¹¹³Nb
42	¹¹⁴Mo
43	¹¹⁵Tc
44	¹¹⁶Ru
45	¹¹⁷Rh	¹²⁵Rh
46	¹¹⁸Pd	¹²⁵Pd
47	¹¹⁹Ag	¹²⁵Ag
48	¹²⁰Cd	¹²⁵Cd
49	¹²¹In	¹²⁵In
50	¹²²Sn	¹²⁵Sn
51	¹²³Sb	¹²⁵Sb
52	¹²⁴Te	¹²⁵Te
53	¹²⁵I	¹²⁵I
54	¹²⁶Xe	¹²⁵Xe
55	¹²⁷Cs	¹²⁵Cs
56	¹²⁸Ba	¹²⁵Ba
57	¹²⁹La	¹²⁵La
58	¹³⁰Ce	¹²⁵Ce
59	¹³¹Pr	¹²⁵Pr
60	¹³²Nd	¹²⁵Nd
61	¹³³Pm
62	¹³⁴Sm
63	¹³⁵Eu
64	¹³⁶Gd
65	¹³⁷Tb
66	¹³⁸Dy