Uranium-243

Properties and data of the isotope ²⁴³U.

Contents

Uranium-243 is a radioisotope of the chemical element uranium, which, in addition to the element-specific 92 protons, has 151 neutrons in the atomic nucleus, resulting in the mass number 243. The very short-lived, only artificially producible, unstable and therefore radioactive nuclide has no practical significance; dealing with ²⁴³U is for academic purposes only.

The nuclide was indirectly detected in the fallout of the thermonuclear test (Ivy Mike) on November 1, 1952 in the Pacific Ocean [1]; there is no confirmation to date. The data given here are theoretical or estimated.

See also: List of individual Uranium isotopes (and general data sources).

General data

Name of the isotope:Uranium-243; U-243Symbol:²⁴³U or 24392UMass number A:243 (= number of nucleons)Atomic number Z:92 (= number of protons)Neutrons N:151Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.6413043478261 (= neutron-proton ratio)Neutron excess (N-Z):59Isotopic mass:243.06708(32) u (atomic weight of Uranium-243)Nuclide mass:243.0166173 u (calculated nuclear mass without electrons)Mass excess:62.48462 MeVMass defect:1.96122526 u (per nucleus)Nuclear binding energy:1826.86956234 MeV (per nucleus)
7.51798174 MeV (average binding energy per nucleon)Separation energy:S_N = 4.211 MeV (first neutron)Half-life:10 sDecay constant λ:0.069314718055995 s^-1Specific activity α:1.717790106172 × 10⁺²⁰ Bq g^-1
4642675962.6292 Ci g^-1Spin and parity:
(nuclear angular momentum)

Radioactive Decay

Half-life T_½ = 10 s respectively 1 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁴³Np	?	2.67 MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 151) and isobaric (same nucleon number A = 243) with Uranium-243. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 151	Isobar A = 243
92	²⁴³U	²⁴³U
93	²⁴⁴Np	²⁴³Np
94	²⁴⁵Pu	²⁴³Pu
95	²⁴⁶Am	²⁴³Am
96	²⁴⁷Cm	²⁴³Cm
97	²⁴⁸Bk	²⁴³Bk
98	²⁴⁹Cf	²⁴³Cf
99	²⁵⁰Es	²⁴³Es
100	²⁵¹Fm	²⁴³Fm
101	²⁵²Md
102	²⁵³No
103	²⁵⁴Lr
104	²⁵⁵Rf
105	²⁵⁶Db
106	²⁵⁷Sg

Literature and References

[1] - H. Diamond, P. R. Fields, C. S. Stevens et al.:
Heavy Isotope Abundances in Mike Thermonuclear Device.
In: Physical Review, 119, 2000, (1960), DOI 10.1103/PhysRev.119.2000.