Input interpretation
Ac-208 (actinium-208)
Decay properties
half-life | 95 ms (milliseconds) (70 to 130 ms) mean lifetime | 140 ms (milliseconds) (90 to 190 ms) decay constant | 7.3 per second specific activity | 2.1×10^10 TBq/g (terabecquerels per gram) width | 3.3×10^-15 eV (electronvolts) decay modes | α (alpha emission) | β^+ (positron emission) final decay products | Hg-196 (60%) | Hg-200 (40%) | Pb-204 (5×10^-4) | Pt-192 (6×10^-6) | Pb-208 (4×10^-10) | Os-188 (3×10^-13) | Os-184 (7×10^-20) | Hf-176 (0) | Hf-180 (0) | Pt-196 (0) | W-180 (0) | W-184 (0)
Decay modes
decay mode | α (alpha emission) branching ratio | 99% Q-value | 7.7268 MeV (megaelectronvolts) daughter nuclide | Fr-204 decay mode | β^+ (positron emission) branching ratio | 1% Q-value | 8.0241 MeV (megaelectronvolts) daughter nuclide | Ra-208
Decay chain
Decay chain
Mass properties
atomic number (Z) | 89 mass number (A) | 208 neutron number | 119 atomic mass | 208.011551551 u (unified atomic mass units) mass excess | 10.760201 MeV (megaelectronvolts) binding energy per nucleon | 7.684831 MeV (megaelectronvolts)
Mass properties
Nearby isotopes
Nearby isotopes
Quantum properties
spin parity J^π | 3^+ (atomic fermion)
Quantum properties
Excitations
E_level | spin parity J^π | half-life τ_1/2 | width Δ 506 keV (kiloelectronvolts) | 10^- | 0.025 seconds | 1.8×10^-14 eV (electronvolts)