Thallium-187m
Properties and data of the isotope 187mTl.
See also: List of individual Thallium isotopes (and general data sources).
General data
Name of the isotope:Thallium-187m; Tl-187mSymbol:187mTl or 187m81TlMass number A:187 (= number of nucleons)Atomic number Z:81 (= number of protons)Neutrons N:106Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.3086419753086 (= neutron-proton ratio)Neutron excess (N-Z):25Excitation energy:334(4) keVIsotopic mass:186.975905(9) u (atomic weight of Thallium-187m)Nuclide mass:186.931475 u (calculated nuclear mass without electrons)Mass excess:-22.44435 MeVMass defect:1.576403688 u (per nucleus)Nuclear binding energy:1468.41057695 MeV (per nucleus)
7.85246298 MeV (average binding energy per nucleon)Half-life:15.60(12) sDecay constant λ:0.044432511574355 s-1Specific activity α:1.438595932588 × 10+20 Bq g-1
3888097115.1051 Ci g-1Spin and parity:
(nuclear angular momentum)(9/2-)Magnetic dipole moment:μ(μN) = + 3.79(2)Quadrupole moment Q:- 2.43(5) barn (100 fm2)Nuclear g-factor:gl = 0.84222222222222
Radioactive Decay
Half-life T½ = 15.60(12) s respectively 1.560 × 101 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| EC/β+ | 187Hg | 0.15(5) % | | |
| α | 183Au | ? | | |
| Iso | 187Tl | < 99.9 % | | |
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 |
|---|
| 187Tl | | ca. 51 s | (1/2+) |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 106) and isobaric (same nucleon number A = 187) with Thallium-187m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 106 | Isobar A = 187 |
|---|
| 64 | 170Gd | |
| 65 | 171Tb | |
| 66 | 172Dy | |
| 67 | 173Ho | |
| 68 | 174Er | |
| 69 | 175Tm | |
| 70 | 176Yb | |
| 71 | 177Lu | 187Lu |
| 72 | 178Hf | 187Hf |
| 73 | 179Ta | 187Ta |
| 74 | 180W | 187W |
| 75 | 181Re | 187Re |
| 76 | 182Os | 187Os |
| 77 | 183Ir | 187Ir |
| 78 | 184Pt | 187Pt |
| 79 | 185Au | 187Au |
| 80 | 186Hg | 187Hg |
| 81 | 187Tl | 187Tl |
| 82 | 188Pb | 187Pb |
| 83 | 189Bi | 187Bi |
| 84 | 190Po | 187Po |
| 85 | 191At | |
Last update: 2020-10-22
Perma link: https://www.chemlin.org/isotope/thallium-187m
© 1996 - 2026 ChemLin
