See also: List of individual Mercury isotopes (and general data sources).
General data
Name of the isotope:Mercury-197m; Hg-197mSymbol:197mHg or 197m80HgMass number A:197 (= number of nucleons)Atomic number Z:80 (= number of protons)Neutrons N:117Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4625 (= neutron-proton ratio)Neutron excess (N-Z):37Excitation energy:298.93(8) keVIsotopic mass:196.967214(3) u (atomic weight of Mercury-197m)Nuclide mass:196.9233324 u (calculated nuclear mass without electrons)Mass excess:-30.53996 MeVMass defect:1.672583732 u (per nucleus)Nuclear binding energy:1558.00171086 MeV (per nucleus) 7.90863813 MeV (average binding energy per nucleon)Half-life:23.8(1) hDecay constant λ:8.089953087767 × 10-6 s-1Specific activity α:2.473449019608 × 10+16 Bq g-1 668499.73502935 Ci g-1Spin and parity: (nuclear angular momentum)13/2+Quadrupole moment Q:+1.25(3) barn (100 fm2)
Radioactive Decay
Half-life T½ = 23.8(1) h (hours) respectively 8.5680 × 104 seconds s.
Decay mode
Daughter
Probability
Decay energy
γ energy (intensity)
EC/β+
197Au
8.6(7) %
Iso
197Hg
91.4(7) %
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 = 197) with Mercury-197m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
