Uranium-228

Properties and data of the isotope ²²⁸U.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Uranium-228; U-228Symbol:²²⁸U or 22892UMass number A:228 (= number of nucleons)Atomic number Z:92 (= number of protons)Neutrons N:136Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.4782608695652 (= neutron-proton ratio)Neutron excess (N-Z):44Isotopic mass:228.031371(15) u (atomic weight of Uranium-228)Nuclide mass:227.9809083 u (calculated nuclear mass without electrons)Mass excess:29.2219 MeVMass defect:1.86696052 u (per nucleus)Nuclear binding energy:1739.06252262 MeV (per nucleus)
7.6274672 MeV (average binding energy per nucleon)Separation energy:S_N = 7.895(17) MeV (first neutron)
S_P = 4.898(16) MeV (first proton)Half-life:9.1(2) minDecay constant λ:0.0012695003306959 s^-1Specific activity α:3.35311833911 × 10⁺¹⁸ Bq g^-1
90624819.976135 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1949

Radioactive Decay

Half-life T_½ = 9.1(2) min (minutes) respectively 5.46 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²²⁴Th	> 95 %	6.804(10) MeV
EC	²²⁸Pa	< 5 %	0.299(15) MeV

Parent Nuclides

Direct parent isotope is: ²³²Pu.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 136) and isobaric (same nucleon number A = 228) with Uranium-228. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 136	Isobar A = 228
80	²¹⁶Hg
81	²¹⁷Tl
82	²¹⁸Pb
83	²¹⁹Bi
84	²²⁰Po
85	²²¹At	²²⁸At
86	²²²Rn	²²⁸Rn
87	²²³Fr	²²⁸Fr
88	²²⁴Ra	²²⁸Ra
89	²²⁵Ac	²²⁸Ac
90	²²⁶Th	²²⁸Th
91	²²⁷Pa	²²⁸Pa
92	²²⁸U	²²⁸U
93	²²⁹Np	²²⁸Np
94	²³⁰Pu	²²⁸Pu
95	²³¹Am
96	²³²Cm
97	²³³Bk