Iodine-137

Properties and data of the isotope ¹³⁷I.

Content

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

General data

Name of the isotope:Iodine-137; I-137Other names:Jod-137Symbol:¹³⁷I or 13753IMass number A:137 (= number of nucleons)Atomic number Z:53 (= number of protons)Neutrons N:84Isotopic mass:136.918028(9) u (atomic weight of Iodine-137)Nuclide mass:136.8889551 u (calculated nuclear mass without electrons)Mass excess:-76.35643 MeVMass defect:1.22455164 u (per nucleus)Nuclear binding energy:1140.66250535 MeV (per nucleus)
8.32600369 MeV (average binding energy per nucleon)Separation energy:S_N = 4.882(16) MeV (first neutron)
S_P = 9.220(9) MeV (first proton)Half-life:24.5(2) sDecay constant λ:0.028291721655508 s^-1Specific activity α:1.252770095438 × 10⁺²⁰ Bq g^-1
3385865122.8059 Ci g^-1Spin and parity:
(nuclear angular momentum)(7/2+)Year of discovery:1943

Radioactive Decay

Half-life T_½ = 24.5(2) s respectively 2.45 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹³⁷Xe	92.86 %	6.027(8) MeV
β^-, n	¹³⁶Xe	7.14 %	2.002(8) MeV

Parent Nuclides

Direct parent isotopes are: ¹³⁷Te, ²⁴⁸Cm.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 84) and isobaric (same nucleon number A = 137) with Iodine-137. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 84	Isobar A = 137
47	¹³¹Ag
48	¹³²Cd
49	¹³³In	¹³⁷In
50	¹³⁴Sn	¹³⁷Sn
51	¹³⁵Sb	¹³⁷Sb
52	¹³⁶Te	¹³⁷Te
53	¹³⁷I	¹³⁷I
54	¹³⁸Xe	¹³⁷Xe
55	¹³⁹Cs	¹³⁷Cs
56	¹⁴⁰Ba	¹³⁷Ba
57	¹⁴¹La	¹³⁷La
58	¹⁴²Ce	¹³⁷Ce
59	¹⁴³Pr	¹³⁷Pr
60	¹⁴⁴Nd	¹³⁷Nd
61	¹⁴⁵Pm	¹³⁷Pm
62	¹⁴⁶Sm	¹³⁷Sm
63	¹⁴⁷Eu	¹³⁷Eu
64	¹⁴⁸Gd	¹³⁷Gd
65	¹⁴⁹Tb	¹³⁷Tb
66	¹⁵⁰Dy
67	¹⁵¹Ho
68	¹⁵²Er
69	¹⁵³Tm
70	¹⁵⁴Yb
71	¹⁵⁵Lu
72	¹⁵⁶Hf
73	¹⁵⁷Ta
74	¹⁵⁸W
75	¹⁵⁹Re