Americium-243

Properties and data of the isotope ²⁴³Am.

Content

General Data

Radioactive Decay

Parent Nuclides

NMR Data

Isotones und Isobares

Literature

Americium-243 is the radioisotope of the element Americium, whose atomic nucleus has 148 neutrons in addition to the element-specific 95 protons, resulting in a mass number of 243: ²⁴³Am.

General data

Name of the isotope:Americium-243; Am-243Symbol:²⁴³Am or 24395AmMass number A:243 (= number of nucleons)Atomic number Z:95 (= number of protons)Neutrons N:148Isotopic mass:243.0613799(15) u (atomic weight of Americium-243)Nuclide mass:243.009272 u (calculated nuclear mass without electrons)Mass excess:57.17501 MeVMass defect:1.964405708 u (per nucleus)Nuclear binding energy:1829.83213057 MeV (per nucleus)
7.53017338 MeV (average binding energy per nucleon)Separation energy:S_N = 6.3643(12) MeV (first neutron)
S_P = 4.8309(14) MeV (first proton)Half-life:7353(10) aDecay constant λ:2.984744350686 × 10^-12 s^-1Specific activity α:7396934531.1667 Bq g^-1
0.19991714949099 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μ_N) = + 1.50(1)Charge radius:5.9048(35) femtometer fmYear of discovery:1950

Radioactive Decay

(Note: For the value of the half-life: cf. [1] ).

Half-life T_½ = 7353(10) a respectively 2.3223 × 10¹¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²³⁹Np	ca. 100 %	5.4391(9) MeV
SZ	^div	trace

Parent Nuclides

Direct parent isotopes are: ²⁴⁷Bk, ²⁴³Cm, ²⁴³Pu.

Occurrence

Comparison of the natural Americium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Americium Isotopic mixture	243.061382541 u	100 %
Isotope ²⁴³Am	243.0613799(15) u	100 %	7353(10) a	5/2-

NMR data

Nuclear magnetic properties of the NMR active Nuclide ²⁴³Am

Isotope:²⁴³Am-NMRQuantity:100 %Spin:5/2-Nuclearmagnetic moment
μ/μ_N:+ 1.50(1)Gyromagnetic ratio γ:1.54 · 10⁷ rad T^-1 s^-1Nuclear g-factor:g_l = 0.6Quadrupole moment Q:+4.32(6) barn (100 fm²)Line width parameter (factor):l = 59719.68 fm⁴Resonance frequency:v₀ = 4.6 at 1 TRelative Sensitivity:0.01446 (H₀ = const.)
1.2532 (v₀ = const.)
[related to ¹H = 1.000]

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 148) and isobaric (same nucleon number A = 243) with Americium-243. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 148	Isobar A = 243
90	²³⁸Th
91	²³⁹Pa
92	²⁴⁰U
93	²⁴¹Np	²⁴³Np
94	²⁴²Pu	²⁴³Pu
95	²⁴³Am	²⁴³Am
96	²⁴⁴Cm	²⁴³Cm
97	²⁴⁵Bk	²⁴³Bk
98	²⁴⁶Cf	²⁴³Cf
99	²⁴⁷Es	²⁴³Es
100	²⁴⁸Fm	²⁴³Fm
101	²⁴⁹Md
102	²⁵⁰No
103	²⁵¹Lr

External data and identifiers

CAS:14993-75-0InChI Key:LXQXZNRPTYVCNG-IGMARMGPSA-NSMILES:[243Am]PubChem:ID 105139Adopted Levels, Gammas:NuDat 243Am

Literature and References

[1] - M. Marouli, S. Pommé, V. Jobbágy et al.:
Absolute and relative measurement of the ²⁴³Am half-life.
In: Journal of Radioanalytical and Nuclear Chemistry, (2020), DOI 10.1007/s10967-020-07450-9.