Uranium-235
Properties and data of the isotope 235U.
See also: List of individual Uranium isotopes (and general data sources).
General data
Name of the isotope:Uranium-235; U-235Other names:Actinuran. Actinouran. ActinouraniumSymbol:235U or 23592UMass number A:235 (= number of nucleons)Atomic number Z:92 (= number of protons)Neutrons N:143Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.554347826087 (= neutron-proton ratio)Neutron excess (N-Z):51Isotopic mass:235.04393(2) u (atomic weight of Uranium-235)Nuclide mass:234.9934673 u (calculated nuclear mass without electrons)Mass excess:40.92053 MeVMass defect:1.915055932 u (per nucleus)Nuclear binding energy:1783.86311032 MeV (per nucleus)
7.59090685 MeV (average binding energy per nucleon)Separation energy:SN = 5.29750(23) MeV (first neutron)
SP = 6.709(4) MeV (first proton)Half-life:7.04(1) × 108 aDecay constant λ:3.122095583762 × 10-17 s-1Specific activity α:80007.231419595 Bq g-1
2.16235760593 × 10-6 Ci g-1Spin and parity:
(nuclear angular momentum)7/2-Magnetic dipole moment:μ(μN) = - 0.38(3)Charge radius:5.8337(41) femtometer fmYear of discovery:1935
Radioactive Decay
Half-life T½ = 7.04(1) × 108 a respectively 2.2201344 × 1016 seconds s.
Decay
mode | Daughter | Probability | Decay energy | γ energy
(intensity) |
|---|
| α | 231Th | ca. 100 % | 4.6780(7) MeV | |
| SZ | div | trace | | |
Parent Nuclides
Direct parent isotopes are: 239Pu, 235Np, 235Pa.
Occurrence
Comparison of the natural Uranium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):
| | Atomic Mass ma | Quantity | Half-life | Spin |
|---|
Uranium
Isotopic mixture | 238.02891 u | 100 % | | |
| Isotope 234U | 234.04095(2) u | 0.0054(5) % | 2.455(6) × 105 a | 0+ |
| Isotope 235U | 235.04393(2) u | 0.7204(6) % | 7.04(1) × 108 a | 7/2- |
| Isotope 238U | 238.050787618(15) u | 99.2742(10) % | 4.468(6) × 109 a | 0+ |
NMR data
Nuclear magnetic properties and parameters of the NMR active Nuclide 235U
Isotope:235U-NMRQuantity:0.7204(6) %Spin:7/2-Nuclearmagnetic moment
μ/μN:- 0.38(3)Gyromagnetic ratio γ:0.4926 · 107 rad T-1 s-1
0.78400 MHz T-1Nuclear g-factor:gl = -0.10857142857143Quadrupole moment Q:+ 4.936(6) barn (100 fm2)Resonance frequency:v0 = 0.83 MHz at 1 TRelative Sensitivity:[related to 1H = 1.000]:
0.00015 (H0 = const.)
0.4082 (v0 = const.)
Nuclear Isomers
Nuclear isomers or excited states with the activation energy in keV related to the ground state.
| Nuclear Isomer | Excitation Energy | Half-life | Spin |
|---|
| 235mU | 0.0760(4) keV | ca. 26 min | 1/2+ |
| 235m2U | 2500(300) keV | 3.6(19) ms | |
Isotones and Isobars
The following table shows the atomic nuclei that are isotonic (same neutron number N = 143) and isobaric (same nucleon number A = 235) with Uranium-235. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
| Z | Isotone N = 143 | Isobar A = 235 |
|---|
| 84 | 227Po | |
| 85 | 228At | |
| 86 | 229Rn | |
| 87 | 230Fr | |
| 88 | 231Ra | |
| 89 | 232Ac | 235Ac |
| 90 | 233Th | 235Th |
| 91 | 234Pa | 235Pa |
| 92 | 235U | 235U |
| 93 | 236Np | 235Np |
| 94 | 237Pu | 235Pu |
| 95 | 238Am | 235Am |
| 96 | 239Cm | 235Cm |
| 97 | 240Bk | 235Bk |
| 98 | 241Cf | |
| 99 | 242Es | |
| 100 | 243Fm | |
| 101 | 244Md | |
External data and identifiers
CAS:15117-96-1InChI Key:JFALSRSLKYAFGM-OIOBTWANSA-NSMILES:[235U]PubChem:ID 61784Adopted Levels, Gammas:NuDat 235U
Last update: 2021-03-15
Perma link: https://www.chemlin.org/isotope/uranium-235
© 1996 - 2026 ChemLin
