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Nickel (Ni) is the element with atomic number 28, symbol Ni. It has five stable isotopes. Its nuclei are thought be the product of supernova nucleosynthesis. Nickel-58 (i.e., mass number 58) is the most common isotope; several nucleosynthesis paths lead to it. Nickel-56 nuclei are created by the alpha process, but are unstable, generally decaying into iron-56 through two beta decays. Nickel-62 is very stable, having the highest binding energy of any nucleus (even more than iron-56), but is not abundant because nucleosynthesis paths to it include low-probability steps.