Zinc-70

Main isotopes of zinc

Iso­tope Decay abun­dance half-life mode energy (MeV) pro­duct 64Zn 49.2% is stable with 34 neutrons 65Zn syn 244 d ε 1.3519 65Cu γ 1.1155 – 66Zn 27.7% is stable with 36 neutrons 67Zn 4.0% is stable with 37 neutrons 68Zn 18.5% is stable with 38 neutrons 69Zn syn 56 min β− 0.906 69Ga 69mZn syn 13.8 h β− 0.906 69Ga 70Zn 0.6% is stable with 40 neutrons 71Zn syn 2.4 min β− 2.82 71Ga 71mZn syn 4 d β− 2.82 71Ga 72Zn syn 46.5 h β− 0.458 72Ga
Standard atomic weight (Ar)	65.38(2)

Naturally occurring zinc (₃₀Zn) is composed of the 5 stable isotopes ⁶⁴Zn, ⁶⁶Zn, ⁶⁷Zn, ⁶⁸Zn, and ⁷⁰Zn with ⁶⁴Zn being the most abundant (48.6% natural abundance). Twenty-five radioisotopes have been characterised with the most abundant and stable being ⁶⁵Zn with a half-life of 244.26 days, and ⁷²Zn with a half-life of 46.5 hours. All of the remaining radioactive isotopes have half-lives that are less than 14 hours and the majority of these have half-lives that are less than 1 second. This element also has 10 meta states.

Zinc has been proposed as a "salting" material for nuclear weapons (cobalt is another, better-known salting material). A jacket of isotopically enriched ⁶⁴Zn, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope ⁶⁵Zn with a half-life of 244 days and produce approximately 1.115 MeV of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several days. Such a weapon is not known to have ever been built, tested, or used.

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