Input interpretation
Ac-209 (actinium-209)
Decay properties
half-life | 100 ms (milliseconds) (0 to 200 ms) mean lifetime | 144 ms (milliseconds) (-8 to 290 ms) decay constant | 6.93 per second specific activity | 2×10^10 TBq/g (terabecquerels per gram) width | 3.16×10^-15 eV (electronvolts) decay modes | α (alpha emission) | β^+ (positron emission) final decay products | Au-197 (70%) | Hg-201 (29%) | Tl-205 (1%) | Ir-193 (7×10^-7) | Os-189 (7×10^-14)
Decay modes
decay mode | α (alpha emission) branching ratio | 99% Q-value | 7.7292 MeV (megaelectronvolts) daughter nuclide | Fr-205 decay mode | β^+ (positron emission) branching ratio | 1% Q-value | 5.9673 MeV (megaelectronvolts) daughter nuclide | Ra-209
Decay chain
Decay chain
Mass properties
atomic number (Z) | 89 mass number (A) | 209 neutron number | 120 atomic mass | 209.009494863 u (unified atomic mass units) mass excess | 8.844409 MeV (megaelectronvolts) binding energy per nucleon | 7.695847 MeV (megaelectronvolts)
Mass properties
Nearby isotopes
Nearby isotopes
Quantum properties
spin parity J^π | 9/2^- (atomic boson)
Quantum properties