Polonium-195m
Properties and data of the isotope 195mPo.
See also: List of individual Polonium isotopes (and general data sources).
General data
Name of the isotope:Polonium-195m; Po-195mSymbol:195mPo or 195m84PoMass number A:195 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:111Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.3214285714286 (= neutron-proton ratio)Neutron excess (N-Z):27Excitation energy:230 keVIsotopic mass:194.98813(4) u (atomic weight of Polonium-195m)Nuclide mass:194.9420547 u (calculated nuclear mass without electrons)Mass excess:-11.05683 MeVMass defect:1.630978364 u (per nucleus)Nuclear binding energy:1519.2465602 MeV (per nucleus)
7.791008 MeV (average binding energy per nucleon)Half-life:1.92(2) sDecay constant λ:0.36101415654164 s-1Specific activity α:1.120658816043 × 10+21 Bq g-1
30288076109.292 Ci g-1Spin and parity:
(nuclear angular momentum)(13/2+)Magnetic dipole moment:μ(μN) = -0.932(65)Quadrupole moment Q:+1.30(45) barn (100 fm2)Nuclear g-factor:gl = -0.14338461538462
Radioactive Decay
Half-life T½ = 1.92(2) s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| α | 191Pb | ca. 90 % | | |
| EC/β+ | 195Bi | ca. 10 % | | |
| Iso | 195Po | < 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 |
|---|
| 195Po | | 4.64(9) s | (3/2-) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 111) and isobaric (same nucleon number A = 195) with Polonium-195m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 111 | Isobar A = 195 |
|---|
| 70 | 181Yb | |
| 71 | 182Lu | |
| 72 | 183Hf | |
| 73 | 184Ta | |
| 74 | 185W | 195W |
| 75 | 186Re | 195Re |
| 76 | 187Os | 195Os |
| 77 | 188Ir | 195Ir |
| 78 | 189Pt | 195Pt |
| 79 | 190Au | 195Au |
| 80 | 191Hg | 195Hg |
| 81 | 192Tl | 195Tl |
| 82 | 193Pb | 195Pb |
| 83 | 194Bi | 195Bi |
| 84 | 195Po | 195Po |
| 85 | 196At | 195At |
| 86 | 197Rn | 195Rn |
External data and identifiers
Last update: 2020-10-07
Perma link: https://www.chemlin.org/isotope/polonium-195m
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