Uranium-222

Properties and data of the isotope ²²²U.

Contents

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

General data

Name of the isotope:Uranium-222; U-222Symbol:²²²U or 22292UMass number A:222 (= number of nucleons)Atomic number Z:92 (= number of protons)Neutrons N:130Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.4130434782609 (= neutron-proton ratio)Neutron excess (N-Z):38Isotopic mass:222.02606(6) u (atomic weight of Uranium-222)Nuclide mass:221.9755973 u (calculated nuclear mass without electrons)Mass excess:24.27473 MeVMass defect:1.820282024 u (per nucleus)Nuclear binding energy:1695.58178366 MeV (per nucleus)
7.63775578 MeV (average binding energy per nucleon)Separation energy:S_N = 8.32(7) MeV (first neutron)
S_P = 3.39(7) MeV (first proton)Half-life:4.7(7) mu;sDecay constant λ:147478.12352339 s^-1Specific activity α:4.000603755031 × 10⁺²⁶ Bq g^-1
1.081244258116 × 10⁺¹⁶ Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1983

Radioactive Decay

Half-life T_½ = 4.7(7) mu;s respectively 4.7 × 10^-6 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²¹⁸Th	100 %	9.48(5) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 130) and isobaric (same nucleon number A = 222) with Uranium-222. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 130	Isobar A = 222
78	²⁰⁸Pt
79	²⁰⁹Au
80	²¹⁰Hg
81	²¹¹Tl
82	²¹²Pb
83	²¹³Bi	²²²Bi
84	²¹⁴Po	²²²Po
85	²¹⁵At	²²²At
86	²¹⁶Rn	²²²Rn
87	²¹⁷Fr	²²²Fr
88	²¹⁸Ra	²²²Ra
89	²¹⁹Ac	²²²Ac
90	²²⁰Th	²²²Th
91	²²¹Pa	²²²Pa
92	²²²U	²²²U
93	²²³Np	²²²Np