Isotopes of zinc
Naturally occurring zinc is composed of the 5 stable isotopes 64Zn, 66Zn, 67Zn, 68Zn, and 70Zn with 64Zn being the most abundant. Twenty-eight radioisotopes have been characterised with the most stable being 65Zn with a half-life of 243.94 days, and then 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 a second. This element also has 10 meta states.
Zinc has been proposed as a "salting" material for nuclear weapons. A jacket of isotopically enriched 64Zn, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would be transmuted to 65Zn, which emits 1.115 MeV of gamma radiation in about half of decays, and would significantly increase the radioactivity of the weapon's fallout for several years. Such a weapon is not known to have ever been built, tested, or used.