Lead-197m2
Properties and data of the isotope 197m2Pb.
See also: List of individual Lead isotopes (and general data sources).
General data
Name of the isotope:Lead-197m2; Pb-197m2Symbol:197m2Pb or 197m282PbMass number A:197 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:115Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4024390243902 (= neutron-proton ratio)Neutron excess (N-Z):33Excitation energy:1914.10(25) keVIsotopic mass:196.973435(5) u (atomic weight of Lead-197m2)Nuclide mass:196.9284566 u (calculated nuclear mass without electrons)Mass excess:-24.74514 MeVMass defect:1.664682964 u (per nucleus)Nuclear binding energy:1550.64219287 MeV (per nucleus)
7.87128017 MeV (average binding energy per nucleon)Half-life:1.15(20) μsDecay constant λ:602736.67874778 s-1Specific activity α:1.851921010647 × 10+27 Bq g-1
5.005191920669 × 10+16 Ci g-1Spin and parity:
(nuclear angular momentum)21/2-Magnetic dipole moment:μ(μN) = -0.531(6)Nuclear g-factor:gl = -0.050571428571429Year of discovery:1978
Radioactive Decay
Half-life T½ = 1.15(20) μs respectively 1.15 × 10-6 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| Iso | 197Pb | 100 % | | |
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 |
|---|
| 197Pb | | 8.1(17) min | 3/2- |
| 197m1Pb | 319.31(11) keV | 42.9(9) min | 13/2+ |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 115) and isobaric (same nucleon number A = 197) with Lead-197m2. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 115 | Isobar A = 197 |
|---|
| 70 | 185Yb | |
| 71 | 186Lu | |
| 72 | 187Hf | |
| 73 | 188Ta | |
| 74 | 189W | 197W |
| 75 | 190Re | 197Re |
| 76 | 191Os | 197Os |
| 77 | 192Ir | 197Ir |
| 78 | 193Pt | 197Pt |
| 79 | 194Au | 197Au |
| 80 | 195Hg | 197Hg |
| 81 | 196Tl | 197Tl |
| 82 | 197Pb | 197Pb |
| 83 | 198Bi | 197Bi |
| 84 | 199Po | 197Po |
| 85 | 200At | 197At |
| 86 | 201Rn | 197Rn |
| 87 | 202Fr | |
| 88 | 203Ra | |
| 89 | 204Ac | |
External data and identifiers
Last update: 2025-11-28
Perma link: https://www.chemlin.org/isotope/lead-197m2
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