Isotopes of nickel
Naturally occurring nickel consists of five stable isotopes; Ni, Ni, Ni, Ni and Ni; Ni is the most abundant at over 68%. 26 radioisotopes have been characterized; the most stable are Ni with a half-life of 81,000 years, Ni with a half-life of 101 years, and Ni at 6.075 days. All the other radioactive isotopes have half-lives of less than 60 hours and most of these have half-lives of less than 30 seconds. This element also has 11 known meta states.
List of isotopes
Notable isotopes
The known isotopes of nickel range in mass number from Ni to Ni, and include:Nickel-48, discovered in 1999, is the most neutron-poor nickel isotope known. With 28 protons and 20 neutrons Ni is "doubly magic" and therefore much more stable, with a half-life around 3 milliseconds, than would be expected from its position in the chart of nuclides. It has the highest ratio of protons to neutrons of any known doubly magic nuclide.
Nickel-56, also doubly magic, is produced in large quantities in supernovae. In the last phases of stellar evolution of very large stars, fusion of lighter elements like hydrogen and helium comes to an end. Later in the star's life cycle, elements including magnesium, silicon, and sulfur are fused to form heavier elements. Once the last nuclear fusion reactions cease, the star collapses to produce a supernova. During the supernova, silicon burning produces Ni. This isotope of nickel is favored because it has an equal number of neutrons and protons, making it readily produced by fusing two Si atoms. Ni is the last element that can be formed in the alpha process. Past Ni, nuclear reactions are endoergic and energetically unfavorable. Ni decays to Co and then Fe by β+ decay. The radioactive decay of Ni and Co supplies much of the energy for the light curves observed for stellar supernovae. The shape of the light curve of these supernovae display characteristic timescales corresponding to the decay of Ni to Co and then to Fe.
Nickel-58 is the most abundant isotope of nickel with a 68.077% natural abundance. It is the only isotope theoretically unstable toward double beta decay.
Nickel-59 is a long-lived cosmogenic radionuclide with a half-life of 81,000 years. Ni has found many applications in isotope geology. Ni has been used to date the terrestrial age of meteorites and to determine abundances of extraterrestrial dust in ice and sediment.
Nickel-60 is the daughter product of the extinct radionuclide . Because Fe has such a long half-life, its persistence in materials in the Solar System at high enough concentrations may have generated observable variations in the isotopic composition of Ni. Therefore, the abundance of Ni in extraterrestrial material may provide insight into the origin of the Solar System and its early history/very early history. Unfortunately, nickel isotopes appear to have been heterogeneously distributed in the early Solar System. Therefore, so far, no actual age information has been attained from Ni excesses. Ni is also the stable end-product of the decay of Zn, the last rung of the alpha ladder.
Nickel-61 is the only stable isotope of nickel with a nuclear spin, which makes it useful for studies by EPR spectroscopy.
Nickel-62 has the highest binding energy per nucleon of any isotope for any element, when including the electron shell in the calculation, though iron-56 has the lower mass-energy per nucleon. Though fusion could form heavier isotopes exothermically - for example, two Ca atoms could make Kr and liberate 77 keV per nucleon - reactions leading to the iron/nickel region are more probable as they release more energy in total.
Nickel-63 has two main uses: detection of explosives traces, and in certain kinds of electronic devices, such as gas discharge tubes used as surge protectors. A surge protector is a device that protects sensitive electronic equipment like computers from sudden changes in the electric current flowing into them. It is also used in electron capture detectors in gas chromatography for the detection mainly of halogens. It is proposed to be used for miniature betavoltaic generators for pacemakers.
Nickel-64 is the heaviest stable isotope of nickel.
Nickel-78 is one of the element's heaviest known isotopes. With 28 protons and 50 neutrons, nickel-78 is doubly magic, resulting in much greater nuclear binding energy and stability despite a lopsided neutron-proton ratio. Its half-life is milliseconds. Due to its magic neutron number, Ni is believed to have an important role in supernova nucleosynthesis of elements heavier than iron. Ni, along with N = 50 isotones Cu and Zn, are thought to constitute a waiting point in the r-process, where further neutron capture is delayed by the shell gap and a buildup of isotopes around A = 80 results.