Antimony-126

Properties and data of the isotope ¹²⁶Sb.

Content

General data

Name of the isotope:Antimony-126; Sb-126Symbol:¹²⁶Sb or 12651SbMass number A:126 (= number of nucleons)Atomic number Z:51 (= number of protons)Neutrons N:75Isotopic mass:125.90725(3) u (atomic weight of Antimony-126)Nuclide mass:125.8792741 u (calculated nuclear mass without electrons)Mass excess:-86.39607 MeVMass defect:1.141695332 u (per nucleus)Nuclear binding energy:1063.48235159 MeV (per nucleus)
8.44033612 MeV (average binding energy per nucleon)Separation energy:S_N = 6.21(3) MeV (first neutron)
S_P = 7.79(3) MeV (first proton)Half-life:12.35(6) dDecay constant λ:6.49598122432 × 10^-7 s^-1Specific activity α:3.129577116509 × 10⁺¹⁵ Bq g^-1
84583.165311059 Ci g^-1Spin and parity:
(nuclear angular momentum)(8-)Magnetic dipole moment:μ(μ_N) = 1.28(7)Nuclear g-factor:g_l = 0.16Year of discovery:1956

Radioactive Decay

Half-life T_½ = 12.35(6) d respectively 1.067040 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹²⁶Te	100 %	3.67(3) MeV

Parent Nuclides

Direct parent isotope is: ¹²⁶Sn.

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
^126m1Sb	17.7(3) keV	19.15(8) min	(5+)
^126m2Sb	40.4(3) keV	11 s	(3-)
^126m3Sb	104.6(3) keV	553(5) ns	(3+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 75) and isobaric (same nucleon number A = 126) with Antimony-126. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 75	Isobar A = 126
42	¹¹⁷Mo
43	¹¹⁸Tc
44	¹¹⁹Ru
45	¹²⁰Rh	¹²⁶Rh
46	¹²¹Pd	¹²⁶Pd
47	¹²²Ag	¹²⁶Ag
48	¹²³Cd	¹²⁶Cd
49	¹²⁴In	¹²⁶In
50	¹²⁵Sn	¹²⁶Sn
51	¹²⁶Sb	¹²⁶Sb
52	¹²⁷Te	¹²⁶Te
53	¹²⁸I	¹²⁶I
54	¹²⁹Xe	¹²⁶Xe
55	¹³⁰Cs	¹²⁶Cs
56	¹³¹Ba	¹²⁶Ba
57	¹³²La	¹²⁶La
58	¹³³Ce	¹²⁶Ce
59	¹³⁴Pr	¹²⁶Pr
60	¹³⁵Nd	¹²⁶Nd
61	¹³⁶Pm	¹²⁶Pm
62	¹³⁷Sm
63	¹³⁸Eu
64	¹³⁹Gd
65	¹⁴⁰Tb
66	¹⁴¹Dy
67	¹⁴²Ho
68	¹⁴³Er
69	¹⁴⁴Tm