Zirconium-96

Main isotopes of zirconium

Iso­tope Decay abun­dance half-life (t1/2) mode pro­duct 88Zr syn 83.4 d ε 88Y γ – 89Zr syn 78.4 h ε 89Y β+ 89Y γ – 90Zr 51.45% is stable 91Zr 11.22% is stable 92Zr 17.15% is stable 93Zr trace 1.53×106 y β− 93Nb 94Zr 17.38% is stable 96Zr 2.80% 2.0×1019 y β−β− 96Mo
Standard atomic weight (Ar)	91.224(2)

Naturally occurring zirconium (₄₀Zr) is composed of four stable isotopes (of which one may in the future be found radioactive), and one very long-lived radioisotope (⁹⁶Zr), a primordial nuclide that decays via double beta decay with an observed half-life of 2.0×10¹⁹ years; it can also undergo single beta decay, which is not yet observed, but the theoretically predicted value of t_1/2 is 2.4×10²⁰ years. The second most stable radioisotope is ⁹³Zr, which has a half-life of 1.53 million years. Twenty-seven other radioisotopes have been observed. All have half-lives less than a day except for ⁹⁵Zr (64.02 days), ⁸⁸Zr (63.4 days), and ⁸⁹Zr (78.41 hours). The primary decay mode is electron capture for isotopes lighter than ⁹²Zr, and the primary mode for heavier isotopes is beta decay.

Zirconium is the heaviest element that can be formed from symmetric fusion, from either ⁴⁵Sc, or ⁴⁶Ca producing ⁹⁰Zr (after two beta-plus decays from ⁹⁰Mo) and ⁹²Zr respectively. All heavier elements are formed either through asymmetric fusion or during the collapse of supernovae. As most of these are energy-absorbing processes, most nuclides of elements heavier than zirconium are theoretically unstable to spontaneous fission, although in many cases, the half-life for this is too long to have been observed. See list of nuclides for a tabulation.

⁸⁹Zr is a radioisotope of zirconium with a half-life of 78.41 hours. It is produced by proton irradiation of natural yttrium-89. Its most prominent gamma photon has an energy of 909 keV.

Zirconium-89 is employed in specialized diagnostic applications using positron emission tomography imaging, for example, with zirconium-89 labeled antibodies (immuno-PET). For a decay table, see Maria Vosjan. "Zirconium-89 (⁸⁹Zr)". Cyclotron.nl. 

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