Tellurium-125m

Properties and data of the isotope ¹²⁵Te.

Content

General data

Name of the isotope:Tellurium-125m; Te-125mSymbol:¹²⁵Te or 12552TeMass number A:125 (= number of nucleons)Atomic number Z:52 (= number of protons)Neutrons N:73Isotopic mass:124.9044312(15) u (atomic weight of Tellurium-125m)
Excitation energy: 144.775(8) keVNuclide mass:124.8759068 u (calculated nuclear mass without electrons)Mass excess:-89.02176 MeVMass defect:1.135009332 u (per nucleus)Nuclear binding energy:1057.2543827 MeV (per nucleus)
8.45803506 MeV (average binding energy per nucleon)Half-life:57.40(15) dDecay constant λ:1.397654496870 × 10^-7 s^-1Specific activity α:6.787800204578 × 10⁺¹⁴ Bq g^-1
18345.405958321 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2-Magnetic dipole moment:μ(μ_N) = - 0.985(6)Quadrupole moment Q:- 0.06(2) barn (100 fm²)Nuclear g-factor:g_l = -0.17909090909091

Radioactive Decay

Half-life T_½ = 57.40(15) d respectively 4.959360 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹²⁵Te	100 %		0.035504(15) MeV 7.30(7) %

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
¹²⁵Te		stable	1/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 73) and isobaric (same nucleon number A = 125) with Tellurium-125m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 73	Isobar A = 125
41	¹¹⁴Nb
42	¹¹⁵Mo
43	¹¹⁶Tc
44	¹¹⁷Ru
45	¹¹⁸Rh	¹²⁵Rh
46	¹¹⁹Pd	¹²⁵Pd
47	¹²⁰Ag	¹²⁵Ag
48	¹²¹Cd	¹²⁵Cd
49	¹²²In	¹²⁵In
50	¹²³Sn	¹²⁵Sn
51	¹²⁴Sb	¹²⁵Sb
52	¹²⁵Te	¹²⁵Te
53	¹²⁶I	¹²⁵I
54	¹²⁷Xe	¹²⁵Xe
55	¹²⁸Cs	¹²⁵Cs
56	¹²⁹Ba	¹²⁵Ba
57	¹³⁰La	¹²⁵La
58	¹³¹Ce	¹²⁵Ce
59	¹³²Pr	¹²⁵Pr
60	¹³³Nd	¹²⁵Nd
61	¹³⁴Pm
62	¹³⁵Sm
63	¹³⁶Eu
64	¹³⁷Gd
65	¹³⁸Tb
66	¹³⁹Dy
67	¹⁴⁰Ho