Iodine-133

Properties and data of the isotope ¹³³I.

Content

General data

Name of the isotope:Iodine-133; I-133Other names:Jod-133Symbol:¹³³I or 13353IMass number A:133 (= number of nucleons)Atomic number Z:53 (= number of protons)Neutrons N:80Isotopic mass:132.907827(7) u (atomic weight of Iodine-133)Nuclide mass:132.8787541 u (calculated nuclear mass without electrons)Mass excess:-85.8586 MeVMass defect:1.200092976 u (per nucleus)Nuclear binding energy:1117.87940659 MeV (per nucleus)
8.40510832 MeV (average binding energy per nucleon)Separation energy:S_N = 8.226(8) MeV (first neutron)
S_P = 7.959(7) MeV (first proton)Half-life:20.83(8) hDecay constant λ:9.243441358083 × 10^-6 s^-1Specific activity α:4.217068627950 × 10⁺¹⁶ Bq g^-1
1139748.2778244 Ci g^-1Spin and parity:
(nuclear angular momentum)7/2+Magnetic dipole moment:μ(μ_N) = + 2.856(5)Quadrupole moment Q:0.024(1) barn (100 fm²)Nuclear g-factor:g_l = 0.816Year of discovery:1940

Radioactive Decay

Half-life T_½ = 20.83(8) h (hours) respectively 7.4988 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹³³Xe	100 %	1.785(7) MeV

Parent Nuclides

Direct parent isotope is: ¹³³Te.

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^133m1I	1634.148(10) keV	9(2) s	(19/2-)
^133m2I	1729.137(10) keV	170 ns	(15/2-)
^133m3I	2435.00(23) keV	0.78(16) μs	(19/2+)
^133m4I	2493.7(4) keV	469(15) ns	(23/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 80) and isobaric (same nucleon number A = 133) with Iodine-133. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 80	Isobar A = 133
44	¹²⁴Ru
45	¹²⁵Rh
46	¹²⁶Pd
47	¹²⁷Ag
48	¹²⁸Cd	¹³³Cd
49	¹²⁹In	¹³³In
50	¹³⁰Sn	¹³³Sn
51	¹³¹Sb	¹³³Sb
52	¹³²Te	¹³³Te
53	¹³³I	¹³³I
54	¹³⁴Xe	¹³³Xe
55	¹³⁵Cs	¹³³Cs
56	¹³⁶Ba	¹³³Ba
57	¹³⁷La	¹³³La
58	¹³⁸Ce	¹³³Ce
59	¹³⁹Pr	¹³³Pr
60	¹⁴⁰Nd	¹³³Nd
61	¹⁴¹Pm	¹³³Pm
62	¹⁴²Sm	¹³³Sm
63	¹⁴³Eu	¹³³Eu
64	¹⁴⁴Gd
65	¹⁴⁵Tb
66	¹⁴⁶Dy
67	¹⁴⁷Ho
68	¹⁴⁸Er
69	¹⁴⁹Tm
70	¹⁵⁰Yb
71	¹⁵¹Lu