Input interpretation
At-212 (astatine-212)
Decay properties
half-life | 314 ms (milliseconds) (311.4 to 316.6 ms) mean lifetime | 453 ms (milliseconds) (420 to 456.2 ms) decay constant | 2.21 per second specific activity | 6.27×10^9 TBq/g (terabecquerels per gram) width | 1.45×10^-15 eV (electronvolts) decay modes | α (alpha emission) | β^+ (positron emission) | β^- (electron emission) final decay products | Pb-208 (100%) | Pb-204 (2×10^-6%) | Hg-200 (0%)
Decay modes
decay mode | α (alpha emission) branching ratio | 100% Q-value | 7.82392 MeV (megaelectronvolts) daughter nuclide | Bi-208 decay mode | β^+ (positron emission) branching ratio | 0.03% Q-value | 726.03 keV (kiloelectronvolts) daughter nuclide | Po-212 decay mode | β^- (electron emission) branching ratio | 2×10^-6% Q-value | 38.42 keV (kiloelectronvolts) daughter nuclide | Rn-212
Radiation shielding
lead | 27 µm water | 75.6 µm air | 68.8 mm
Decay chain
Decay chain
Mass properties
atomic number (Z) | 85 mass number (A) | 212 neutron number | 127 atomic mass | 211.990744771 u (unified atomic mass units) mass excess | -8.62119 MeV (megaelectronvolts) binding energy per nucleon | 7.798306 MeV (megaelectronvolts)
Mass properties
Nearby isotopes
Nearby isotopes
Quantum properties
spin parity J^π | 1^- (atomic fermion)
Quantum properties
Excitations
E_level | spin parity J^π | half-life τ_1/2 | width Δ 55 keV (kiloelectronvolts) | 1^- or 2^- (uncertain) | 1×10^-9 seconds | 4.6×10^-7 eV (electronvolts) 160.4 keV (kiloelectronvolts) | 2^- | (unknown) | (unknown) 205.6 keV (kiloelectronvolts) | 3^- | (unknown) | (unknown) 223 keV (kiloelectronvolts) | 9^- | 0.119 seconds | 3.83×10^-15 eV (electronvolts) 275.5 keV (kiloelectronvolts) | 5^- | 3.2×10^-8 seconds | 1.4×10^-8 eV (electronvolts) 328.1 keV (kiloelectronvolts) | 8^- | 1×10^-9 seconds | 4.6×10^-7 eV (electronvolts) 345.7 keV (kiloelectronvolts) | ?^- | (unknown) | (unknown) 363.7 keV (kiloelectronvolts) | 1^- or 2^- (uncertain) | (unknown) | (unknown) 622.6 keV (kiloelectronvolts) | ?^- | (unknown) | (unknown) 635.3 keV (kiloelectronvolts) | (unknown) | (unknown) | (unknown)