Emergence of californium as the second transitional element in the actinide series
نویسندگان
چکیده
A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, and show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. The metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence.
منابع مشابه
CHAPTER ELEVEN CALIFORNIUM Richard
The discovery of californium came in the era of the syntheses and identifications of other transplutonium elements, following the end of World War II. The discovery of the element californium, like many of the other actinide elements, hinged on the development of new experimental techniques in conjunction with predictions based on nuclear systematics. Californium was named after the University ...
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A late actinide with twenty known isotopes, californium is a manmade transuranic element that does not occur naturally. It was first identified by Glenn Seaborg and co-workers in February 1950 in an experiment that used a 60-inch cyclotron to bombard curium-242 targets with helium ions. Although named primarily for the State of California, it also recognizes the University of California at Berk...
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Several questions of importance in the study of lanthanide and actinide coordination compounds are reviewed. There is considerable evidence that in aqueous solution the primary coordination number is nine for the ions La(ni) through Nd(m) and eight for the ions heavier than Gd(m). While it seems that some degree of covalency exists in the metal—ligand bonding a model of electrostatic bonding se...
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The participation of the valence orbitals of actinides in bonding has been debated for decades. Recent experimental and computational investigations demonstrated the involvement of 6p, 6d and/or 5f orbitals in bonding. However, structural and spectroscopic data, as well as theory, indicate a decrease in covalency across the actinide series, and the evidence points to highly ionic, lanthanide-li...
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عنوان ژورنال:
دوره 6 شماره
صفحات -
تاریخ انتشار 2015