Chemistry of actinide elements

The General Chemistry of Actinide Elements.—The chemical separation of kurchatovium, Ku, has been claimed and discussed. Pu was bom-... 

Previous results of the preparation chemistry of actinide elements have been reviewed in detail by F. WeigeF In the following chapter, the actual state of the possibihties for the preparation and refining of actinide metals will be described the principles and trends in synthesis and crystal growth of (simple) actinide compounds will be shown. 

Katz, J.J., Seaborg, G.T., Morss, L.R., 1986. The Chemistry of Actinide Elements. Chapman and Hall, London. 

J. J. Katz, G.T. Seaborg, Khimiya actinidnykh elementov (Chemistry of Actinide Elements). Moscow, Atomizdat, 1958, p. 542. 

The environmental chemistry of actinide elements at very low solution concentrations (nano-, pico-, or femto-molar), or in association with endemic environmental materials is poorly understood. There is evidence that chemical speciation and transformation of actinide elements in different environments will play a... 

Hel man has not continued her very interesting research on the synthesis of compounds containing a multiplicity of unidentate groups, for it is excellent work. For some years now she has been involved in the chemistry of actinide elements. 

Katz JJ, Seaborg GT, Morss LR (1986) The chemistry of actinide elements, 2nd ed, vols 1 and 2, Chapman and Hall, New York... 

Pentavalent and hexavalent actinide elements take oxygenated actinyl ions AnOa and An02 (An = actinide elements). Stable pentavalent neptunium takes the Np02 type structure in solution. The relationship between oxidation states and structural variation is fundamental information for solution and separation chemistry of actinide elements. As these actinyl ions, An02 and An02, are less acidic than the An ions, the tendency of hydrolysis decreases in the order, An " > An02 > An > An02. ... 

One of the most significant examples of the application of XANES in the chemistry of actinide elements was reported by Conradson et al. (1998). They measured Lm XANES spectra... 

Ion exchange (qv see also Chromatography) is an important procedure for the separation and chemical identification of curium and higher elements. This technique is selective and rapid and has been the key to the discovery of the transcurium elements, in that the elution order and approximate peak position for the undiscovered elements were predicted with considerable confidence (9). Thus the first experimental observation of the chemical behavior of a new actinide element has often been its ion-exchange behavior—an observation coincident with its identification. Further exploration of the chemistry of the element often depended on the production of larger amounts by this method. Solvent extraction is another useful method for separating and purifying actinide elements. 

There are two principal routes by which the actinides can enter the body uptake can occur either via inhalation or by oral uptake as contaminants of food. However, as both routes of uptake require the actinides to cross a variety of cellular barriers it is necessary to be familiar with some of the chemistry of these elements. 

Dr. Darleane C. Hoffman of the Nuclear Science Division of the Lawrence Berkeley National Laboratory and Department of Chemistry at the University of California at Berkeley has written and presented several papers documenting her work and that of her team on the laboratory production of transactinide and actinide elements one-atom-at-a-time. She explains the difficulty of determining the chemistry of heavy elements How long does an atom need to exist before it s possible to do any meaningful chemistry on it Is it possible to learn anything at all about the reactions of an element for which no more... 

The review is divided into three sections, (i) the chemistry of scandium and yttrium, (ii) the chemistry of the lanthanide elements, further subdivided into a survey of lanthanide n.m.r. shift reagents and the general chemistry of the elements, and (iii) the chemistry of the actinide elements and uranyl and related compounds. 

This, the second volume of the series, covers the period October 1971 to September 1972 and follows the layout previously adopted in Volume 1 with only a few minor variations (see List of Contents). Thus Chapter 1 contains an account of the Chemistry of the Early Transition Metals excluding Scandium, Yttrium, and the Lanthanides. The Chemistry of the Elements of the first transition series Manganese to Copper is discussed in Chapter 2. Chapter 3 deals with the Noble Metals (Ru, Os, Rh, Ir, Pd, Pt, Ag, and Au) and Chapter 4 the Lanthanides (including Sc,Y, and La) and Actinides. 

Moore, C. E. Ionization Potentials and Ionization Limits Derived from the Analyses of Optical Spectra, NSRDS-NBS 34 National Bureau of Standards Washington. DC, 1970, except for the data on the actinides, which are from The Chemistry ofthe Actinide Elements, Katz, J. J. Seaborg, G. T. Morss, L. R., Eds. Qiapman and Hall New York, 1986 Vol. 2. 

The orgarometallic chemistry of actinides. ignored in the early development of the field, is currently receiving a great deal of attention.1 7 In many instances the chemistry of this group of elements is unlike that of the transition metals. For example, it has been shown that a thorium hydride, in contrast to the manganese hydride shown above, does undergo CO insertion.138... 

Despite the extremely low concentrations of the transuranium elements in water, most of the environmental chemistry of these elements has been focused on their behavior in the aquatic environment. One notes that the neutrality of natural water (pH = 5-9) results in extensive hydrolysis of the highly charged ions except for Pu(V) and a very low solubility. In addition, natural waters contain organics as well as micro- and macroscopic concentrations of various inorganic species such as metals and anions that can compete with, complex, or react with the transuranium species. The final concentrations of the actinide elements in the environment are thus the result of a complex set of competing chemical reactions such as hydrolysis, complexation, redox reactions, and colloid formation. As a consequence, the aqueous environmental chemistry of the transuranium elements is significantly different from their ordinary solution chemistry in the laboratory. 

The chemistry of actinides is more complicated due to the existence of greater range of oxidation states for these metals. Moreover, all these metals are radioactive and therefore, their accessibility for laboratory investigations is limited. The elements beyond uranium are all man-made elements and are made by nuclear-chemical methods. 

The actinide elements (which are all radioactive) up to Z = 103 are listed in Table 20-1 along with some of their properties. The principal isotopes that can be obtained in macroscopic amounts are listed in Table 20-2. The significance of the term actinide series is justified by the overall agreement of the chemistry of these elements with that concept, although it is not as clearly justified as is the lanthanide concept. Note in Table 20-1 that some irregular variation in the 5f/6d electron distribution does occur. 

The analytical chemistry of the transition elements see Transition Metals), that is, those with partly filled shells of d (see (f Configuration) or f electrons see f-Block Metals), should include that of the first transition period (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) and that of the second transition series (Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag). The third transition series embraces Hf, Ta, W, Re, Os, Ir, Pt, and An, and although it formally begins with lanthanum, for historical reasons this element is usually included with the lanthanoids (rare-earth elements) see Scandium, Yttrium the Lanthanides Inorganic Coordination Chemistry Rare Earth Elements). The actinoid elements see Actinides Inorganic Coordination Chemistry) are all radioactive see Radioactive Decay) and those with atomic number see Atomic Number) greater than uranium (Z = 92) are artificial the analytical chemistry of these elements is too specialized to consider here. 

Zinc tetraphenylporphyrinate forms a weak complex with Of in non-aqueous solutions. The bonding in this complex appears to be essentially ionic . We have already mentioned crystal structure determinations of lanthanide and actinide compounds. There is every reason to suppose that these elements have a rich dioxygen complex chemistry and this is confirmed by two recent papers For reasons of space, however, we shall not discuss the dioxygen complex chemistry of these elements. 

---