Mercury-205m
Properties and data of the isotope 205mHg.
See also: List of individual Mercury isotopes (and general data sources).
General data
Name of the isotope:Mercury-205m; Hg-205mSymbol:205mHg or 205m80HgMass number A:205 (= number of nucleons)Atomic number Z:80 (= number of protons)Neutrons N:125Isotopic mass:204.976073(4) u (atomic weight of Mercury-205m)
Excitation energy: 1556.40(17) keVNuclide mass:204.9321914 u (calculated nuclear mass without electrons)Mass excess:-22.28786 MeVMass defect:1.73304406 u (per nucleus)Nuclear binding energy:1614.32014363 MeV (per nucleus)
7.87473241 MeV (average binding energy per nucleon)Half-life:1.09(4) msDecay constant λ:635.91484455041 s-1Specific activity α:1.877239592552 × 10+24 Bq g-1
50736205204124 Ci g-1Spin and parity:
(nuclear angular momentum)13/2+
Radioactive Decay
Half-life T½ = 1.09(4) ms respectively 1.09 × 10-3 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| Iso | 205Hg | 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 |
|---|
| 205Hg | | 5.14(9) min | 1/2- |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 205) with Mercury-205m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 125 | Isobar A = 205 |
|---|
| 76 | 201Os | |
| 77 | 202Ir | 205Ir |
| 78 | 203Pt | 205Pt |
| 79 | 204Au | 205Au |
| 80 | 205Hg | 205Hg |
| 81 | 206Tl | 205Tl |
| 82 | 207Pb | 205Pb |
| 83 | 208Bi | 205Bi |
| 84 | 209Po | 205Po |
| 85 | 210At | 205At |
| 86 | 211Rn | 205Rn |
| 87 | 212Fr | 205Fr |
| 88 | 213Ra | 205Ra |
| 89 | 214Ac | 205Ac |
| 90 | 215Th | |
| 91 | 216Pa | |
| 92 | 217U | |
Last update: 2020-10-22
Perma link: https://www.chemlin.org/isotope/mercury-205m
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