Specific aspects of metals

The outer electrons in metals such as Li and Na have a very low ionization energy, and are largely delocalized. Such electrons are described as constituting a nearly free electron gas. It may be noted, though, that this description is somewhat misleading as the behavior of the electrons is dominated by the exclusion principle, while the molecules in normal gases can be described by classical statistical mechanics. 

The Fermi surface plays an important role in the theory of metals. It is defined by the reciprocal-space wavevectors of the electrons with largest kinetic energy, and is the highest occupied molecular orbital (HOMO) in molecular orbital theory. For a free electron gas, the Fermi surface is spherical, that is, the kinetic energy of the electrons is only dependent on the magnitude, not on the direction of the wavevector. In a free electron gas the electrons are completely delocalized and will not contribute to the intensity of the Bragg reflections. As a result, an accurate scale factor may not be obtainable from a least-squares refinement with neutral atom scattering factors. 

Because the effect of bonding on the electron density of metals is relatively small, charge density studies on metals require very careful collection of intensity data. The number of available studies is limited, but important conclusions have been reached. 

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Part I of the book details various industrial operations and waste streams and suggested methods of treatment. Part II contains 25 papers, presented at a symposium, which deal with specific aspects of metal-bearing waste management alternatives. 

This review does not attempt an exhaustive survey of all NMR work on catalysts, and its reference list is not a suitable guide to the historical development of the general subject. Papers on adsorbate NMR have typically been selected because they address some specific aspect of metallic behavior (or a pointed lack of it). Due to the availability of additional information, the reasoning and the interpretation of results given here are sometimes different from those in the original papers. 

Recent abundance ratio work in this field falls into two categories. The first category has been investigations into aspects of metal-poor AGB and Type la SN yields and their relationship to the chemical evolution in the dSph galaxies, e.g. McWilliam et al. (2003), Venn et al. (2004), McWilliam Smecker-Hane (2005). In these works the abundances of specific elements are compared to... 

During an investigation of the properties of low melting metals, a specific aspect of the alloying behaviour of Sn and Pb has been studied by Guminski (1989,1990),... 

While investigating the properties of low melting metals, a specific aspect of the alloying behaviour of Bi has been studied by Guminski (1989, 1990) who compiled and discussed the data concerning the solubility of the different elements in this metal. Solubility data at 600°C have been plotted and discussed as a function of the atomic number curves showing periodic variations were obtained with trends very similar to those obtained for Hg, Ga, In, Sn and Pb (with very deep minima, for instance, for the elements in positions close to Mo and W). 

Molecular mechanics have become more and more important in the study of the correlation between cavity size and ionic radius of coordinated metal ions (84CCR1, 93CCR177). The different aspects of metal ion reactivity and ligand design for specific and selective binding can be modeled and understood in detail. 

The coordination chemistries of the elements considered in this chapter have already been the subject of detailed discussion in earlier sections of these volumes. Consequently, it is the purpose of this chapter to review, in general terms, the nuclear fuel cycle, the production of metal radionuclides and subsequently their incorporation into radiopharmaceutical formulations. Within this framework, specific aspects of coordination chemistry which are relevant to the application in question will be considered. 

It is over eight years since the last comprehensive review appeared on metal isocyanide chemistry. In the interim, reviews have appeared on specific aspects of isocyanide chemistry. Lippard reviewed seven and eight coordination in molybdenum isocyanide compounds (7), Yamamoto reviewed metal(O)- isocyanide complexes (2), and in related reviews on car-bene complexes by Cotton and Lukehart (5), Lappert et al. (4), and Casey (5), mention was made of carbenes synthesized from metal isocyanides. 

After a treatment of general aspects of metals in the marine environment, specific target organisms, mainly bivalves (clams, mussels, oysters) and tunicates are considered. The latter class of marine organisms, commonly referred to as sea squirts, allows us to trace the pathway of a specific element, vanadium, from outer to inner environment. 

This article is concerned with one specific aspect of cluster organometallic chemistry, and describes the synthesis, characterization, structure, and reactivity of transition metal clusters containing alkyne, or alkyne-derived ligands. Alkynes display a diverse reactivity in their reactions with carbonyl clusters, and exhibit a wider range of coordination modes than any other simple, unsaturated molecule. It is this compelling diversity that has prompted the authors to undertake this review. 

Other important toxicological con tarn in ants that can be found in waste-waters are metals. Toxic heavy metal ions are introduced to aquatic streams by means of various industrial activities viz. nfrning, refining ores, fertilizer industries, tanneries, batteries, paper industries, pesticides, etc., and possess a serious threat to the environment. The major toxic metal ions hazardous to humans as well as other forms of hfe are Cr, Fe, Se, V, Cu, Co, Ni, Cd, Hg, As, Pb, Zn, etc. These heavy metals are of specific concern due to their toxicity, bioaccumulation tendency, and persistency in nature [190]. The SLM technique has been widely apphed for the transport and recovery of almost ah important metals from various matrices an exceUent review of ah aspect of metal permeation through SLM (covering both theoretical and practical considerations) is available [191]. Here, only some selected recent examples of the use of SLM for metal separation whl be presented. 

A number of papers deal with other more specific aspects of the theory of energy transfer. These include the long-time depolarization decay due to excitation transport, enhancement of energy transfer between donor and acceptor molecules near a long metallic wire or dielectric fibre in which guided modes are... 

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