Xenon-139

Properties and data of the isotope ¹³⁹Xe.

Content

General data

Name of the isotope:Xenon-139; Xe-139Symbol:¹³⁹Xe or 13954XeMass number A:139 (= number of nucleons)Atomic number Z:54 (= number of protons)Neutrons N:85Isotopic mass:138.9187922(23) u (atomic weight of Xenon-139)Nuclide mass:138.8891708 u (calculated nuclear mass without electrons)Mass excess:-75.64458 MeVMass defect:1.240277388 u (per nucleus)Nuclear binding energy:1155.31094526 MeV (per nucleus)
8.31158953 MeV (average binding energy per nucleon)Separation energy:S_N = 3.744(4) MeV (first neutron)
S_P = 10.954(6) MeV (first proton)Half-life:39.68(14) sDecay constant λ:0.017468426929434 s^-1Specific activity α:7.622994751490 × 10⁺¹⁹ Bq g^-1
2060268851.7541 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Magnetic dipole moment:μ(μ_N) = - 0.3040(16)Quadrupole moment Q:0.396 barn (100 fm²)Nuclear g-factor:g_l = -0.20266666666667Charge radius:4.8409(100) femtometer fmYear of discovery:1951

Radioactive Decay

Half-life T_½ = 39.68(14) s respectively 3.968 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹³⁹Cs	100 %	5.056(4) MeV

Parent Nuclides

Direct parent isotopes are: ¹³⁹I, ²⁴⁸Cm, ²⁵²Cf.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 85) and isobaric (same nucleon number A = 139) with Xenon-139. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 85	Isobar A = 139
47	¹³²Ag
48	¹³³Cd
49	¹³⁴In
50	¹³⁵Sn	¹³⁹Sn
51	¹³⁶Sb	¹³⁹Sb
52	¹³⁷Te	¹³⁹Te
53	¹³⁸I	¹³⁹I
54	¹³⁹Xe	¹³⁹Xe
55	¹⁴⁰Cs	¹³⁹Cs
56	¹⁴¹Ba	¹³⁹Ba
57	¹⁴²La	¹³⁹La
58	¹⁴³Ce	¹³⁹Ce
59	¹⁴⁴Pr	¹³⁹Pr
60	¹⁴⁵Nd	¹³⁹Nd
61	¹⁴⁶Pm	¹³⁹Pm
62	¹⁴⁷Sm	¹³⁹Sm
63	¹⁴⁸Eu	¹³⁹Eu
64	¹⁴⁹Gd	¹³⁹Gd
65	¹⁵⁰Tb	¹³⁹Tb
66	¹⁵¹Dy	¹³⁹Dy
67	¹⁵²Ho
68	¹⁵³Er
69	¹⁵⁴Tm
70	¹⁵⁵Yb
71	¹⁵⁶Lu
72	¹⁵⁷Hf
73	¹⁵⁸Ta
74	¹⁵⁹W
75	¹⁶⁰Re
76	¹⁶¹Os