Tellurium-129

Properties and data of the isotope ¹²⁹Te.

Content

General data

Name of the isotope:Tellurium-129; Te-129Symbol:¹²⁹Te or 12952TeMass number A:129 (= number of nucleons)Atomic number Z:52 (= number of protons)Neutrons N:77Isotopic mass:128.9065965(9) u (atomic weight of Tellurium-129)Nuclide mass:128.8780721 u (calculated nuclear mass without electrons)Mass excess:-87.0048 MeVMass defect:1.167503696 u (per nucleus)Nuclear binding energy:1087.5226878 MeV (per nucleus)
8.43040843 MeV (average binding energy per nucleon)Separation energy:S_N = 6.08241(8) MeV (first neutron)
S_P = 9.663(19) MeV (first proton)Half-life:69.6(3) minDecay constant λ:0.00016598352024903 s^-1Specific activity α:7.809188588811 × 10⁺¹⁷ Bq g^-1
21105915.104895 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μ_N) = 0.702(4)Quadrupole moment Q:0.055(13) barn (100 fm²)Nuclear g-factor:g_l = 0.468Year of discovery:1939

Radioactive Decay

Half-life T_½ = 69.6(3) min (minutes) respectively 4.176 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹²⁹I	100 %	1.502(3) MeV

Parent Nuclides

Direct parent isotope is: ¹²⁹Sb.

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
^129mTe	105.51(3) keV	33.6(1) d	11/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 77) and isobaric (same nucleon number A = 129) with Tellurium-129. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 77	Isobar A = 129
43	¹²⁰Tc
44	¹²¹Ru
45	¹²²Rh
46	¹²³Pd	¹²⁹Pd
47	¹²⁴Ag	¹²⁹Ag
48	¹²⁵Cd	¹²⁹Cd
49	¹²⁶In	¹²⁹In
50	¹²⁷Sn	¹²⁹Sn
51	¹²⁸Sb	¹²⁹Sb
52	¹²⁹Te	¹²⁹Te
53	¹³⁰I	¹²⁹I
54	¹³¹Xe	¹²⁹Xe
55	¹³²Cs	¹²⁹Cs
56	¹³³Ba	¹²⁹Ba
57	¹³⁴La	¹²⁹La
58	¹³⁵Ce	¹²⁹Ce
59	¹³⁶Pr	¹²⁹Pr
60	¹³⁷Nd	¹²⁹Nd
61	¹³⁸Pm	¹²⁹Pm
62	¹³⁹Sm	¹²⁹Sm
63	¹⁴⁰Eu
64	¹⁴¹Gd
65	¹⁴²Tb
66	¹⁴³Dy
67	¹⁴⁴Ho
68	¹⁴⁵Er
69	¹⁴⁶Tm