Isotopes of yttrium
Natural yttrium (Y) is composed of a single isotope 89Y. The most stable radioisotopes are 88Y, which has a half-life of 106.6 days and 91Y with a half-life of 58.51 days. All the other isotopes have half-lives of less than a day, except 87Y, which has a half-life of 79.8 hours, and 90Y, with 64 hours. The dominant decay mode below the stable 89Y is electron capture and the dominant mode after it is beta emission. Twenty-six unstable isotopes have been characterized.
90Y exists in equilibrium with its parent isotope strontium-90, which is a product of nuclear fission.
Relative atomic mass: 88.90585(2)
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