See also: List of individual Thallium isotopes (and general data sources).
General data
Name of the isotope:Thallium-206m; Tl-206mSymbol:206mTl or 206m81TlMass number A:206 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:125Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.5432098765432 (= neutron-proton ratio)Neutron excess (N-Z):44Excitation energy:2643.10(18) keVIsotopic mass:205.9761100(14) u (atomic weight of Thallium-206m)Nuclide mass:205.93168 u (calculated nuclear mass without electrons)Mass excess:-22.25339 MeVMass defect:1.740832092 u (per nucleus)Nuclear binding energy:1621.57464871 MeV (per nucleus) 7.8717216 MeV (average binding energy per nucleon)Half-life:3.74(3) minDecay constant λ:0.0030888911789659 s-1Specific activity α:9.031016981559 × 10+18 Bq g-1 244081540.04214 Ci g-1Spin and parity: (nuclear angular momentum)(12-)
Radioactive Decay
Half-life T½ = 3.74(3) min (minutes) respectively 2.244 × 102 seconds s.
Decay mode
Daughter
Probability
Decay energy
γ energy (intensity)
Iso
206Tl
100 %
Nuclear Isomers
Nuclear isomers or excited states with the activation energy in keV related to the ground state.
The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 206) with Thallium-206m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
