Antimony-137

Properties and data of the isotope ¹³⁷Sb.

Content

General data

Name of the isotope:Antimony-137; Sb-137Symbol:¹³⁷Sb or 13751SbMass number A:137 (= number of nucleons)Atomic number Z:51 (= number of protons)Neutrons N:86Isotopic mass:136.93552(6) u (atomic weight of Antimony-137)Nuclide mass:136.9075441 u (calculated nuclear mass without electrons)Mass excess:-60.06273 MeVMass defect:1.208739408 u (per nucleus)Nuclear binding energy:1125.93350612 MeV (per nucleus)
8.21849275 MeV (average binding energy per nucleon)Separation energy:S_N = 3.62(5) MeV (first neutron)
S_P = 11.45(30) MeV (first proton)Half-life:450(50) msDecay constant λ:1.540327067911 s^-1Specific activity α:6.820637186274 × 10⁺²¹ Bq g^-1
184341545574.99 Ci g^-1Spin and parity:
(nuclear angular momentum)(7/2+)Year of discovery:1994

Radioactive Decay

Half-life T_½ = 450(50) ms respectively 4.50 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹³⁷Te	51 %	9.24(5) MeV
β^-, n	¹³⁶Te	49(10) %	6.29(5) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 86) and isobaric (same nucleon number A = 137) with Antimony-137. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 86	Isobar A = 137
48	¹³⁴Cd
49	¹³⁵In	¹³⁷In
50	¹³⁶Sn	¹³⁷Sn
51	¹³⁷Sb	¹³⁷Sb
52	¹³⁸Te	¹³⁷Te
53	¹³⁹I	¹³⁷I
54	¹⁴⁰Xe	¹³⁷Xe
55	¹⁴¹Cs	¹³⁷Cs
56	¹⁴²Ba	¹³⁷Ba
57	¹⁴³La	¹³⁷La
58	¹⁴⁴Ce	¹³⁷Ce
59	¹⁴⁵Pr	¹³⁷Pr
60	¹⁴⁶Nd	¹³⁷Nd
61	¹⁴⁷Pm	¹³⁷Pm
62	¹⁴⁸Sm	¹³⁷Sm
63	¹⁴⁹Eu	¹³⁷Eu
64	¹⁵⁰Gd	¹³⁷Gd
65	¹⁵¹Tb	¹³⁷Tb
66	¹⁵²Dy
67	¹⁵³Ho
68	¹⁵⁴Er
69	¹⁵⁵Tm
70	¹⁵⁶Yb
71	¹⁵⁷Lu
72	¹⁵⁸Hf
73	¹⁵⁹Ta
74	¹⁶⁰W
75	¹⁶¹Re
76	¹⁶²Os