See also: List of individual Bismuth isotopes (and general data sources).
General data
Name of the isotope:Bismuth-208; Bi-208Symbol:208Bi or 20883BiMass number A:208 (= number of nucleons)Atomic number Z:83 (= number of protons)Neutrons N:125Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.5060240963855 (= neutron-proton ratio)Neutron excess (N-Z):42Isotopic mass:207.9797421(25) u (atomic weight of Bismuth-208)Nuclide mass:207.9342152 u (calculated nuclear mass without electrons)Mass excess:-18.87011 MeVMass defect:1.752850056 u (per nucleus)Nuclear binding energy:1632.76931006 MeV (per nucleus) 7.84985245 MeV (average binding energy per nucleon)Separation energy:SN = 6.8869(27) MeV (first neutron) SP = 3.7072(20) MeV (first proton)Half-life:3.68(4) × 105 yearsDecay constant λ:5.972703565713 × 10-14 s-1Specific activity α:172942139.59158 Bq g-1 0.0046741118808535 Ci g-1Spin and parity: (nuclear angular momentum)5+Magnetic dipole moment:μ(μN) = + 4.578(13)Quadrupole moment Q:-0.70(8) barn (100 fm2)Nuclear g-factor:gl = 0.9156Charge radius:5.5147(907) femtometer fmYear of discovery:1953
Radioactive Decay
Half-life T½ = 3.68(4) × 105 years respectively 1.160525 × 1013 seconds s.
The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 208) with Bismuth-208. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
