Polonium-197m
Properties and data of the isotope 197mPo.
See also: List of individual Polonium isotopes (and general data sources).
General data
Name of the isotope:Polonium-197m; Po-197mSymbol:197mPo or 197m84PoMass number A:197 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:113Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.3452380952381 (= neutron-proton ratio)Neutron excess (N-Z):29Excitation energy:204 keVIsotopic mass:196.98566(5) u (atomic weight of Polonium-197m)Nuclide mass:196.9395847 u (calculated nuclear mass without electrons)Mass excess:-13.35762 MeVMass defect:1.650778196 u (per nucleus)Nuclear binding energy:1537.6899849 MeV (per nucleus)
7.80553292 MeV (average binding energy per nucleon)Half-life:32(2) sDecay constant λ:0.021660849392498 s-1Specific activity α:6.655341132015 × 10+19 Bq g-1
1798740846.4906 Ci g-1Spin and parity:
(nuclear angular momentum)(13/2+)Magnetic dipole moment:μ(μN) = -1.053(75)Quadrupole moment Q:+1.26(45) barn (100 fm2)Nuclear g-factor:gl = -0.162
Radioactive Decay
Half-life T½ = 32(2) s respectively 3.2 × 101 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| α | 193Pb | 84(9) % | | |
| EC/β+ | 197Bi | 16(9) % | | |
| Iso | 197Po | 0.01 % | | |
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 |
|---|
| 197Po | | 84(16) s | (3/2-) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 113) and isobaric (same nucleon number A = 197) with Polonium-197m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 113 | Isobar A = 197 |
|---|
| 70 | 183Yb | |
| 71 | 184Lu | |
| 72 | 185Hf | |
| 73 | 186Ta | |
| 74 | 187W | 197W |
| 75 | 188Re | 197Re |
| 76 | 189Os | 197Os |
| 77 | 190Ir | 197Ir |
| 78 | 191Pt | 197Pt |
| 79 | 192Au | 197Au |
| 80 | 193Hg | 197Hg |
| 81 | 194Tl | 197Tl |
| 82 | 195Pb | 197Pb |
| 83 | 196Bi | 197Bi |
| 84 | 197Po | 197Po |
| 85 | 198At | 197At |
| 86 | 199Rn | 197Rn |
| 87 | 200Fr | |
| 88 | 201Ra | |
External data and identifiers
Last update: 2020-10-07
Perma link: https://www.chemlin.org/isotope/polonium-197m
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