Americium-229
Properties and data of the isotope 229Am.
See also: list of Americium isotopes.
General data
Name of the isotope:Americium-229; Am-229Symbol:229Am or 22995AmMass number A:229 (= number of nucleons)Atomic number Z:95 (= number of protons)Neutrons N:134Isotopic mass:229.04525(9) u (atomic weight of Americium-229)Nuclide mass:228.9931421 u (calculated nuclear mass without electrons)Mass excess:42.1501 MeVMass defect:1.859226784 u (per nucleus)Nuclear binding energy:1731.85859394 MeV (per nucleus)
7.56270128 MeV (average binding energy per nucleon)Separation energy:
SP = 1.23(9) MeV (first proton)Half-life:0.9(21-7) sDecay constant λ:0.77016353395549 s-1Specific activity α:2.025342046579 × 10+21 Bq g-1
54738974231.873 Ci g-1Spin and parity:
(nuclear angular momentum)Year of discovery:2015
Radioactive Decay
Half-life T½ = 0.9(21-7) s respectively 9 × 10-1 seconds s.
| Decay mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| α | 225Np | 91 % | 8.14(5) MeV | |
| EE/β+ | 229Pu | 9 % | 4.75(10) MeV | |
Parent Nuclides
Direct parent isotope is: 223Bk.
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 134) and isobaric (same nucleon number A = 229) with Americium-229. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| OZ | Isotone N = 134 | Isobar A = 229 |
|---|
| 80 | 214Hg | |
| 81 | 215Tl | |
| 82 | 216Pb | |
| 83 | 217Bi | |
| 84 | 218Po | |
| 85 | 219At | 229At |
| 86 | 220Rn | 229Rn |
| 87 | 221Fr | 229Fr |
| 88 | 222Ra | 229Ra |
| 89 | 223Ac | 229Ac |
| 90 | 224Th | 229Th |
| 91 | 225Pa | 229Pa |
| 92 | 226U | 229U |
| 93 | 227Np | 229Np |
| 94 | 228Pu | 229Pu |
| 95 | 229Am | 229Am |
Literature and References
[1] - H. M.Devaraja et al.:
Observation of new neutron-deficient isotopes with Z ≥ 92 in multinucleon transfer reactions.
In: Physics Letters B, (2015), DOI 10.1016/j.physletb.2015.07.006.
Last update: 2020-10-23
Perma link: https://www.chemlin.org/isotope/americium-229
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