See also: List of individual Thallium isotopes (and general data sources).
General data
Name of the isotope:Thallium-198m1; Tl-198m1Symbol:198m1Tl or 198m181TlMass number A:198 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:117Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.4444444444444 (= neutron-proton ratio)Neutron excess (N-Z):36Excitation energy:543.6(4) keVIsotopic mass:197.970447(8) u (atomic weight of Thallium-198m1)Nuclide mass:197.926017 u (calculated nuclear mass without electrons)Mass excess:-27.52844 MeVMass defect:1.677175764 u (per nucleus)Nuclear binding energy:1562.27916111 MeV (per nucleus) 7.89029879 MeV (average binding energy per nucleon)Half-life:1.87(3) hDecay constant λ:0.00010296303929886 s-1Specific activity α:3.132073120667 × 10+17 Bq g-1 8465062.4882897 Ci g-1Spin and parity: (nuclear angular momentum)7+Magnetic dipole moment:μ(μN) = 0.641(10)Nuclear g-factor:gl = 0.091571428571429
Radioactive Decay
Half-life T½ = 1.87(3) h (hours) respectively 6.732 × 103 seconds s.
Decay mode
Daughter
Probability
Decay energy
γ energy (intensity)
EC/β+
198Hg
55.9(23) %
Iso
198Tl
44.1(23) %
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 = 117) and isobaric (same nucleon number A = 198) with Thallium-198m1. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
