See also: List of individual Germanium isotopes (and general data sources).
General data
Name of the isotope:Germanium-81; Ge-81Symbol:81Ge or 8132GeMass number A:81 (= number of nucleons)Atomic number Z:32 (= number of protons)Neutrons N:49Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.53125 (= neutron-proton ratio)Neutron excess (N-Z):17Isotopic mass:80.9288329(22) u (atomic weight of Germanium-81)Nuclide mass:80.9112789 u (calculated nuclear mass without electrons)Mass excess:-66.29173 MeVMass defect:0.746149008 u (per nucleus)Nuclear binding energy:695.03332406 MeV (per nucleus) 8.58065832 MeV (average binding energy per nucleon)Separation energy:SN = 4.8277(29) MeV (first neutron) SP = 14.357(4) MeV (first proton)Half-life:7.6(6) sDecay constant λ:0.091203576389466 s-1Specific activity α:6.786713154648 × 10+20 Bq g-1 18342467985.536 Ci g-1Spin and parity: (nuclear angular momentum)(9/2+)Year of discovery:1972
The following table shows the atomic nuclei that are isotonic (same neutron number N = 49) and isobaric (same nucleon number A = 81) with Germanium-81. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
