Antimony-138

Properties and data of the isotope ¹³⁸Sb.

Content

General data

Name of the isotope:Antimony-138; Sb-138Symbol:¹³⁸Sb or 13851SbMass number A:138 (= number of nucleons)Atomic number Z:51 (= number of protons)Neutrons N:87Isotopic mass:137.94179(114) u (atomic weight of Antimony-138)Nuclide mass:137.9138141 u (calculated nuclear mass without electrons)Mass excess:-54.22227 MeVMass defect:1.211134324 u (per nucleus)Nuclear binding energy:1128.164356 MeV (per nucleus)
8.17510403 MeV (average binding energy per nucleon)Separation energy:S_N = 2.23(107) MeV (first neutron)
S_P = 11.72(114) MeV (first proton)Half-life:348(15) msDecay constant λ:1.9918022429883 s^-1Specific activity α:8.755411439718 × 10⁺²¹ Bq g^-1
236632741614 Ci g^-1Spin and parity:
(nuclear angular momentum)(3-)Year of discovery:1994

Radioactive Decay

Half-life T_½ = 348(15) ms respectively 3.48 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy
β^-, n	¹³⁷Te	72(8) %	7.01 MeV
β^-, 2n	¹³⁸Te	?
β^-	¹³⁶Te	?

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 87) and isobaric (same nucleon number A = 138) with Antimony-138. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 87	Isobar A = 138
49	¹³⁶In
50	¹³⁷Sn	¹³⁸Sn
51	¹³⁸Sb	¹³⁸Sb
52	¹³⁹Te	¹³⁸Te
53	¹⁴⁰I	¹³⁸I
54	¹⁴¹Xe	¹³⁸Xe
55	¹⁴²Cs	¹³⁸Cs
56	¹⁴³Ba	¹³⁸Ba
57	¹⁴⁴La	¹³⁸La
58	¹⁴⁵Ce	¹³⁸Ce
59	¹⁴⁶Pr	¹³⁸Pr
60	¹⁴⁷Nd	¹³⁸Nd
61	¹⁴⁸Pm	¹³⁸Pm
62	¹⁴⁹Sm	¹³⁸Sm
63	¹⁵⁰Eu	¹³⁸Eu
64	¹⁵¹Gd	¹³⁸Gd
65	¹⁵²Tb	¹³⁸Tb
66	¹⁵³Dy	¹³⁸Dy
67	¹⁵⁴Ho
68	¹⁵⁵Er
69	¹⁵⁶Tm
70	¹⁵⁷Yb
71	¹⁵⁸Lu
72	¹⁵⁹Hf
73	¹⁶⁰Ta
74	¹⁶¹W
75	¹⁶²Re
76	¹⁶³Os
77	¹⁶⁴Ir