Nuklida · stabil · alami

Hafnium-177 (¹⁷⁷Hf)

Hafnium-177 (¹⁷⁷Hf) adalah isotop stabil hafnium dengan 72 proton dan 105 neutron (nomor massa 177). Kelimpahan alaminya 0.1858(9).

Data nuklida

Unsur: Hafnium (Hf, Z = 72)
Nomor massa (A): 177
Proton (Z): 72
Neutron (N): 105
Massa atom: 176.943230187 ± 0.000001514 u
Waktu paruh: Stable >1.3Ey
Mode peluruhan: Tidak meluruh
Kelimpahan alami: 0.1858(9)
Tahun penemuan: 1934
Sumber data: IAEA Atomic Mass Data Center (NUBASE) and IUPAC CIAAW, via PubChem

Some 176Hf is radiogenic as a result of it being formed as a product of beta decay of radioactive 176Lu (half-life of 3.73×1010 years). Thus, relations between the isotope-amount ratiosn(176Hf)/n(177Hf) and n(176Hf)/n(176Lu) have been used to determine the ages of minerals and rocks. Because of the long half-life of 176Lu, these ratios have been used in geochronology studies that document some of the oldest rocks in the Solar System and on Earth (Fig. IUPAC.72.1). Hafnium isotopic compositions of terrestrial materials evolved differently depending on the relative rates of 176Hf production. Geologists can use calculated lutetium-hafnium ages and the initial isotope-amount ratio n(176Hf)/n(177Hf) along with other isotopic data from the oldest rocks in the Earth to infer that the Earth’s crust differentiated within the first few hundred million years after condensation of the oldest solid matter in the Solar System. Radioactive 182Hf decays to 182W with a half-life of 8.9×106 years, which is much less than the age of meteorites and the Earth. Therefore, measurements of the amounts of hafnium and tungsten isotopes in meteorites and terrestrial samples reveal the earlier presence of 182Hf. As a result, this provides information about chemical differentiation and evolution of the early Solar System,.