Het chemische element uranium, afgekort tot U, met een atoommassa van 238,02891(3) u, heeft geen stabiele isotopen, dus wordt als radioactief element geclassificeerd. In de natuur komen sporen van de radio-isotopen 234U en 235U voor, maar de isotoop 238U komt het meest voor. Dat is met 4,468 miljard jaar de isotoop met de langste halfwaardetijd van uranium. De natuurlijke abundantie ervan bedraagt 99,27%. De kortstlevende isotoop van uranium is 220U, met een halfwaardetijd van ongeveer 60 nanoseconden.
| Nuclide | Z (p) | N (n) | Isotopische massa (u) | Halveringstijd | Radioactief verval | VP | Kernspin | Isotopische verhouding (molfractie) |
Natuurlijk voorkomen (molfractie) |
|---|---|---|---|---|---|---|---|---|---|
| Excitatie-energie | |||||||||
| 217U | 92 | 125 | 217,02437(9) | 26(14) ms | 1/2− | ||||
| 218U | 92 | 126 | 218,02354(3) | 6(5) ms | α | 214Th | 0+ | ||
| 219U | 92 | 127 | 219,02492(6) | 55(25) ms | α | 215Th | 9/2+ | ||
| 220U | 92 | 128 | 220,02472(22) | 60 ns | α | 216Th | 0+ | ||
| β+ (zelden) | 220Pa | ||||||||
| 221U | 92 | 129 | 221,02640(11) | 700 ns | α | 217Th | 9/2+ | ||
| β+ (zelden) | 221Pa | ||||||||
| 222U | 92 | 130 | 222,02609(11) | 1,4(7) ms | α | 218Th | 0+ | ||
| β+ (10−6%) | 222Pa | ||||||||
| 223U | 92 | 131 | 223,02774(8) | 21(8) ms | α | 219Th | 7/2+ | ||
| 224U | 92 | 132 | 224,027605(27) | 940(270) ms | α | 220Th | 0+ | ||
| 225U | 92 | 133 | 225,02939 | 61(4) ms | α | 221Th | (5/2+) | ||
| 226U | 92 | 134 | 226,029339(14) | 269(6) ms | α | 222Th | 0+ | ||
| 227U | 92 | 135 | 227,031156(18) | 1,1(1) min | α | 223Th | (3/2+) | ||
| β+ (0,001%) | 227Pa | ||||||||
| 228U | 92 | 136 | 228,031374(16) | 9,1(2) min | α (95%) | 224Th | 0+ | ||
| EV (5%) | 228Pa | ||||||||
| 229U | 92 | 137 | 229,033506(6) | 58(3) min | β+ (80%) | 229Pa | (3/2+) | ||
| α (20%) | 225Th | ||||||||
| 230U | 92 | 138 | 230,033940(5) | 20,8 dagen | α | 226Th | 0+ | ||
| SS (1,4 × 10−10%) | |||||||||
| β+β+ (zelden) | 230Th | ||||||||
| 231U | 92 | 139 | 231,036294(3) | 4,2(1) dagen | EV | 231Pa | (5/2+) | ||
| α (0,004%) | 227Th | ||||||||
| 232U | 92 | 140 | 232,0371562(24) | 68,9(4) jaar | α | 228Th | 0+ | ||
| CV (8,9 × 10−10%) | 208Pb, 24Ne | ||||||||
| CV (5 × 10−12%) | 204Hg, 28Mg | ||||||||
| SS (10−12%) | |||||||||
| 233U | 92 | 141 | 233,0396352(29) | 1,592(2) × 105 jaar | α | 229Th | 5/2+ | ||
| SS (6 × 10−9%) | |||||||||
| CV (7,2 × 10−11%) | 209Pb, 24Ne | ||||||||
| CV (1,3 × 10−13%) | 205Hg, 28Mg | ||||||||
| 234U | 92 | 142 | 234,0409521(20) | 2,455(6) × 105 jaar | α | 230Th | 0+ | 0,000054(5) | 0,000050 - 0,000059 |
| SS (1,73 × 10−9%) | |||||||||
| CV (1,4 × 10−11%) | 206Hg, 28Mg | ||||||||
| CV (9 × 10−12%) | 184Hf, 26Ne, 24Ne | ||||||||
| 234mU | 1421,32(10) keV | 33,5(20) ms | 6− | ||||||
| 235U | 92 | 143 | 235,0439299(20) | 7,04(1) × 108 jaar | α | 231Th | 7/2− | 0,007204(6) | 0,007198 - 0,007207 |
| SS (7 × 10−9%) | |||||||||
| CV (8 × 10−10%) | 186Hf, 25Ne, 24Ne | ||||||||
| 235mU | 0,0765(4) keV | ± 26 min | IT | 235U | 1/2+ | ||||
| 236U | 92 | 144 | 236,045568(2) | 2,342(3) × 107 jaar | α | 232Th | 0+ | ||
| SS (9,6 × 10−8%) | |||||||||
| 236m1U | 1052,89(19) keV | 100(4) ns | 4− | ||||||
| 236m2U | 2750(10) keV | 120(2) ns | (0+) | ||||||
| 237U | 92 | 145 | 237,0487302(20) | 6,75(1) dagen | β− | 237Np | 1/2+ | ||
| 238U | 92 | 146 | 238,0507882(20) | 4,468(3) × 109 jaar | α | 234Th | 0+ | 0,992742(10) | 0,992739 - 0,992752 |
| SS (5,45 × 10−5%) | |||||||||
| β−β− (2,19 × 10−10%) | 238Pu | ||||||||
| 238mU | 2557,9(5) keV | 280(6) ns | 0+ | ||||||
| 239U | 92 | 147 | 239,0542933(21) | 23,45(2) min | β− | 239Np | 5/2+ | ||
| 239m1 | 20(20) keV | > 250 ns | (5/2+) | ||||||
| 239m2U | 133,7990(10) keV | 780(40) ns | 1/2+ | ||||||
| 240U | 92 | 148 | 240,056592(6) | 14,1(1) uur | β− | 240Np | 0+ | ||
| α (10−10%) | 236Th | ||||||||
| 241U | 92 | 149 | 241,06033(32) | 5 min | β− | 241Np | 7/2+ | ||
| 242U | 92 | 150 | 242,06293(22) | 16,8(5) min | β− | 242Np | 0+ | ||
| 1 | 18 | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | H | 2 | Periodiek systeem | 13 | 14 | 15 | 16 | 17 | He | |||||||||
| 2 | Li | Be | De links verwijzen naar isotopen per element | B | C | N | O | F | Ne | |||||||||
| 3 | Na | Mg | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | Al | Si | P | S | Cl | Ar |
| 4 | K | Ca | Sc | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | Zn | Ga | Ge | As | Se | Br | Kr |
| 5 | Rb | Sr | Y | Zr | Nb | Mo | Tc | Ru | Rh | Pd | Ag | Cd | In | Sn | Sb | Te | I | Xe |
| 6 | Cs | Ba | ↓ | Hf | Ta | W | Re | Os | Ir | Pt | Au | Hg | Tl | Pb | Bi | Po | At | Rn |
| 7 | Fr | Ra | ↓↓ | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og |
| Lanthanoïden | La | Ce | Pr | Nd | Pm | Sm | Eu | Gd | Tb | Dy | Ho | Er | Tm | Yb | Lu | |||
| Actinoïden | Ac | Th | Pa | U | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No | Lr | |||