Input interpretation
U-238 (uranium-238) | U-235 (uranium-235)
Natural abundance
U-238 | U-235 99.2742% | 0.7204%
Decay properties
| U-238 | U-235 half-life | 4.47 Gyr (4.464 to 4.4745 Gyr) | 0.704 Gyr (702.2 to 706.6 Myr) mean lifetime | 6.45 Gyr (6.4453 to 6.4552 Gyr) | 1.02 Gyr (1.014 to 1.019 Gyr) decay constant | 4.916×10^-18 per second | 3.12×10^-17 per second specific activity | 12.44 kBq/g | 79.8 kBq/g width | 3.236×10^-33 eV | 2.05×10^-32 eV decay modes | α (alpha emission) | SF (spontaneous fission) | 2β^- (double beta decay) | α (alpha emission) | SF (spontaneous fission) | ^28Mg (cluster emission) | ^25Ne (cluster emission) | ^20Ne (cluster emission) final decay products | Pb-206 (100%) | Tl-205 (1.9×10^-8) | Pb-208 (2.6×10^-11) | W-184 (9×10^-14) | Yb-168 (5×10^-29) | Er-164 (4×10^-29) | Dy-160 (2×10^-30) | Dy-156 (1×10^-32) | Sm-144 (1×10^-33) | Ce-140 (1×10^-34) | Dy-164 (0) | Er-168 (0) | Gd-156 (0) | Hf-176 (0) | Hf-180 (0) | Sm-152 (0) | Yb-172 (0) | Pb-207 (100%) | Tl-205 (9×10^-10) | Pb-206 (8×10^-12) | Pb-208 (1×10^-14)
Biological properties
| U-235 biological half-life | 15 days biological lifetime | 22 days effective half-life | 15 days effective lifetime | 22 days
Decay modes
U-238
decay mode | α (alpha emission) branching ratio | 100% Q-value | 4.26975 MeV (megaelectronvolts) daughter nuclide | Th-234 decay mode | SF (spontaneous fission) branching ratio | 5.45×10^-7 decay mode | 2β^- (double beta decay) branching ratio | 2.2×10^-12 Q-value | 1.1442 MeV (megaelectronvolts) daughter nuclide | Pu-238
U-235
decay mode | α (alpha emission) branching ratio | 100% Q-value | 4.67826 MeV (megaelectronvolts) daughter nuclide | Th-231 decay mode | SF (spontaneous fission) branching ratio | 7×10^-11 decay mode | ^28Mg (cluster emission) branching ratio | 8×10^-12 daughter nuclide | Hg-207 decay mode | ^25Ne (cluster emission) branching ratio | 8×10^-12 daughter nuclide | Pb-210 decay mode | ^20Ne (cluster emission) branching ratio | 8×10^-12 daughter nuclide | Pb-215
Radiation shielding
| U-238 | U-235 lead | 12.3 µm | 13.8 µm water | 29.8 µm | 34 µm air | 27.1 mm | 31 mm
Decay chain
U-238
Decay chain U-238
U-235
Decay chain U-235
Mass properties
| U-238 | U-235 atomic number (Z) | 92 | 92 mass number (A) | 238 | 235 neutron number | 146 | 143 atomic mass | 238.050788247 u (unified atomic mass units) | 235.043929918 u (unified atomic mass units) mass excess | 47.308948 MeV (megaelectronvolts) | 40.920456 MeV (megaelectronvolts) binding energy per nucleon | 7.57012 MeV (megaelectronvolts) | 7.590907 MeV (megaelectronvolts)
Mass properties