Nickel natural isotopes

Natural isotopes of nickel and their solar abundances... 

Nickel (relative atomic mass = 58.69) is a first-row transition metal in group Vlllb of the periodic table. Although there are five natural isotopes, Ni (68.3%) and Ni (26.1%) are the most abundant. Proteins are often labeled with Ni (nuclear spin, I, is 3/2) to identify the nickel site by EPR spectroscopy, since paramagnetic species with significant spin on Ni exhibit a four-line splitting. Ni, which is a beta emitter with a relatively long half-life of 100 years, can be used to identify Ni-containing proteins and to measure Ni uptake in cells. 

There are five naturally occurring isotopes of nickel nickel-58, nickel-60, nickel-61, nickel-62, and nickel-64. Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element s name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. 

The sulfate and the oxides are important compounds. Natural nickel is a mixture of five stable isotopes nine other unstable isotopes are known. 

The atomic weight increases regularly across the row except for the inversion at cobalt and nickel. We would expect the atomic weight of Ni to be higher than that of Co because there are more protons (28) in the Ni nucleus than in the Co nucleus (27). The reason for the inversion lies in the distribution of naturally occurring isotopes. Natural cobalt consists entirely of the isotope 2 Co natural nickel consists primarily of the isotopes Ni and Ni, the 58-isotope being about three times as abundant as the 60-isotope. 

Corrosion products include iron oxide (Fe203), ferrosoferric oxide (Fe304), nickel oxide (NiO), cobalt oxide (CoO), and complex Fe, Ni, and Co oxides. Cobalt in particular may present a problem (as cobalt59, a naturally occurring isotope), and when present as a contaminant in nickel alloys (such as Inconel 800), may enhance the development of an outer-core radiation field (see Section 7.4.1). 

Derived from the German word meaning devil s copper, nickel is found predominantly in two isotopic forms, Ni (68% natural abundance) and Ni (26%). Ni exists in four oxidation states, 0, I, II, III, and IV. Ni(II), which is the most common oxidation state, has an ionic radius of —65 pm in the four-coordinate state and —80 pm in the octahedral low-spin state. The Ni(II) aqua cation exhibits a pAa of 9.9. It forms tight complexes with histidine (log Af = 15.9) and, among the first-row transition metals, is second only to Cu(II) in its ability to complex with acidic amino acids (log K( = 6-7 (7). Although Ni(II) is most common, the paramagnetic Ni(I) and Ni(III) states are also attainable. Ni(I), a (P metal, can exist only in the S = state, whereas Ni(lll), a cT ion, can be either S = or S =. ... 

ISOTOPES There are 31 Isotopes of nickel, ranging from NI-48 to NI-78. Five of these are stable, and the percentage of their contribution to the element s natural existence on Earth are as follows NI-58 = 68.077%, NI-60 = 26.223%, NI-61 = 1.140%, NI-62 = 3.634%, and NI 64 = 0.926%. All of the other 26 Isotopes of nickel are artificially made and radioactive with half-lives ranging from a few nanoseconds to 7.6x10 years. 

Nickel, palladium and platinum - The low natural abundance of the 61Ni isotope means that there is a paucity of data on NMR spectroscopy of this element, although much useful information can be derived from spectra of ligand nuclei (e.g. Zschunke et al., 1992 Oik et al., 1992). In the case of 105Pd, the large value of the quadrupole moment presents additional difficulties for direct spectroscopic measurements and, as with nickel, NMR studies have concentrated on the characterisation of ligand nuclei. An example here is the application of two-dimensional NMR to investigate the structure of a nucleic acid palladium complex (Bichenkova et al., 1992). 

Foster J. G., Lambert D. D., Frick L. R., and Maas R. (1996) Re-Os isotopic evidence for genesis of Archaean nickel ores in uncontaminated komatiites. Nature 382, 703-706. 

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