Hafnium-177

Main isotopes of hafnium

Iso­tope Decay abun­dance half-life mode energy (MeV) pro­duct 172Hf syn 1.87 y ε 0.350 172Lu 174Hf 0.16% 2×1015 y α 2.495 170Yb 176Hf 5.26% is stable with 104 neutrons 177Hf 18.60% is stable with 105 neutrons 178Hf 27.28% is stable with 106 neutrons 178m2Hf syn 31 y IT 2.446 178Hf 179Hf 13.62% is stable with 107 neutrons 180Hf 35.08% is stable with 108 neutrons 182Hf syn 8.9×106 y β− 0.373 182Ta
Standard atomic weight (Ar)	178.49(2)

Natural hafnium (₇₂Hf) consists of five stable isotopes (¹⁷⁶Hf, ¹⁷⁷Hf, ¹⁷⁸Hf, ¹⁷⁹Hf, and ¹⁸⁰Hf) and one very long-lived radioisotope, ¹⁷⁴Hf, with a half-life of 2×10¹⁵ years. In addition, there are 30 other known radionuclides, the most stable of which is ¹⁸²Hf with a half-life of 8.9×10⁶ years. No other radioisotope has a half-life over 1.87 days. Most isotopes have half-lives under 1 minute. There are also 26 known nuclear isomers, the most stable of which is ^178m2Hf with a half-life of 31 years.

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