Input interpretation
At-217 (astatine-217)
Decay properties
half-life | 32.3 ms (milliseconds) (31.87 to 32.73 ms) mean lifetime | 46.6 ms (milliseconds) (45.98 to 47.22 ms) decay constant | 21.5 per second specific activity | 5.96×10^10 TBq/g (terabecquerels per gram) width | 1.41×10^-14 eV (electronvolts) decay modes | α (alpha emission) | β^- (electron emission) final decay products | Tl-205 (100%)
Decay modes
decay mode | α (alpha emission) branching ratio | 100% Q-value | 7.20129 MeV (megaelectronvolts) daughter nuclide | Bi-213 decay mode | β^- (electron emission) branching ratio | 0.008% Q-value | 736.95 keV (kiloelectronvolts) daughter nuclide | Rn-217
Radiation shielding
lead | 24.2 µm water | 66.2 µm air | 60.3 mm
Decay chain
Decay chain
Mass properties
atomic number (Z) | 85 mass number (A) | 217 neutron number | 132 atomic mass | 217.004718822 u (unified atomic mass units) mass excess | 4.395555 MeV (megaelectronvolts) binding energy per nucleon | 7.744612 MeV (megaelectronvolts)
Mass properties
Nearby isotopes
Nearby isotopes
Quantum properties
spin parity J^π | 9/2^- (atomic boson)
Quantum properties
Excitations
E_level | spin parity J^π | half-life τ_1/2 | width Δ 100.25 keV (kiloelectronvolts) | 7/2^- | 5×10^-10 seconds | 9×10^-7 eV (electronvolts) 218.12 keV (kiloelectronvolts) | 5/2^- | 2.7×10^-10 seconds | 1.7×10^-6 eV (electronvolts) 272.07 keV (kiloelectronvolts) | 3/2^- | (unknown) | (unknown) 310.3 keV (kiloelectronvolts) | (unknown) | (unknown) | (unknown) 368.23 keV (kiloelectronvolts) | 3/2^- | (unknown) | (unknown) 382.34 keV (kiloelectronvolts) | 7/2^- | (unknown) | (unknown) 410.64 keV (kiloelectronvolts) | 13/2^- | (unknown) | (unknown) 424.35 keV (kiloelectronvolts) | 5/2^- or 7/2^- or 9/2^- (uncertain) | (unknown) | (unknown) 537.5 keV (kiloelectronvolts) | 9/2^+ | (unknown) | (unknown) 568.5 keV (kiloelectronvolts) | 7/2 or 9/2 (uncertain) | (unknown) | (unknown)