Xenon-133m

Properties and data of the isotope ¹³³Xe.

Content

General data

Name of the isotope:Xenon-133m; Xe-133mSymbol:¹³³Xe or 13354XeMass number A:133 (= number of nucleons)Atomic number Z:54 (= number of protons)Neutrons N:79Isotopic mass:132.9059107(26) u (atomic weight of Xenon-133m)
Excitation energy: 233.221(15) keVNuclide mass:132.8762893 u (calculated nuclear mass without electrons)Mass excess:-87.64362 MeVMass defect:1.201169392 u (per nucleus)Nuclear binding energy:1118.88208163 MeV (per nucleus)
8.41264723 MeV (average binding energy per nucleon)Half-life:2.198(13) dDecay constant λ:3.649925756158 × 10^-6 s^-1Specific activity α:1.665179320598 × 10⁺¹⁶ Bq g^-1
450048.46502657 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2-Magnetic dipole moment:μ(μ_N) = -1.08241(15)Quadrupole moment Q:+0.77(3) barn (100 fm²)Nuclear g-factor:g_l = -0.19680181818182

Radioactive Decay

Half-life T_½ = 2.198(13) d respectively 1.899072 × 10⁵ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹³³Xe	100 %

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
¹³³Xe		5.2475(5) d	3/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 79) and isobaric (same nucleon number A = 133) with Xenon-133m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 79	Isobar A = 133
44	¹²³Ru
45	¹²⁴Rh
46	¹²⁵Pd
47	¹²⁶Ag
48	¹²⁷Cd	¹³³Cd
49	¹²⁸In	¹³³In
50	¹²⁹Sn	¹³³Sn
51	¹³⁰Sb	¹³³Sb
52	¹³¹Te	¹³³Te
53	¹³²I	¹³³I
54	¹³³Xe	¹³³Xe
55	¹³⁴Cs	¹³³Cs
56	¹³⁵Ba	¹³³Ba
57	¹³⁶La	¹³³La
58	¹³⁷Ce	¹³³Ce
59	¹³⁸Pr	¹³³Pr
60	¹³⁹Nd	¹³³Nd
61	¹⁴⁰Pm	¹³³Pm
62	¹⁴¹Sm	¹³³Sm
63	¹⁴²Eu	¹³³Eu
64	¹⁴³Gd
65	¹⁴⁴Tb
66	¹⁴⁵Dy
67	¹⁴⁶Ho
68	¹⁴⁷Er
69	¹⁴⁸Tm
70	¹⁴⁹Yb
71	¹⁵⁰Lu