Structural and Reactive Properties

The geochemical interpretation of silicate melts is essentially based on three main concepts  

Lux-Flood acid-base properties of dissolved oxides. 

Electrical conductivity measurements on silicate melts indicate an essentially ionic conductivity of unipolar type (Bockris et al., 1952a,b Bockris and Mellors, 1956 Waffe and Weill, 1975). Charge transfer is operated by cations, whereas anionic groups are essentially stationary. Transference of electronic charges (conductivity of h- and n-types) is observed only in melts enriched in transition elements, where band conduction and electron hopping phenomena are favored. We may thus state that silicate melts, like other fused salts, are ionic liquids. 

In an ionic melt, coulombic forces between charges of opposite sign lead to relative short-distance ordering of ions, with anions surrounded by cations and vice versa. The probability of finding a cation replacing an anion in such ordering is effectively zero and, from a statistical point of view, the melt may be considered as a quasi-lattice, with two distinct reticular sites that we will define as anion matrix and cation matrix. 

Let us consider a mixture of two fused salts A Z and B+Y, with A+ and B+ cations and Y and Z anions. The bulk configurational entropy of the mixture is given by the sum of the configurational entropies of the two matrices  

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The above review on the uses of the CP/MAS NMR techniques in the study of the structural and reactivity properties of various types of carbohydrates and aromatic polymers indicates that despite their limitations, the methods have a wide range of applications. 

STRUCTURAL AND REACTIVE PROPERTIES OF SUPPORTED TRANSITION METAL TRIFLATES... 

Structural and Reactive Properties of Supported Transition Metal Triflates... 

Discussion Point DP3 Organic derivatives of the group 13 elements aluminium and boron are needed as essential components for almost all of the insertion-catalyzed olefin polymerizations. List four such compounds of interest and describe for each of them the structural and reactivity properties relevant to its action as activator jcocatalyst. Outline some of the features of polymerization catalysts that do not require any Al- or B-containing cocatalysts. 

Our models are in qualitative agreement with the effect of supercritical conditions of FT synthesis selectivity. A more quantitative analysis of such effects requires more detailed information on the structural and reactive properties of the catalysts used in such studies (123,124) and on the rates of CO, H2, and hydrocarbon diffusion in supercritical hydrocarbons. We suggest that recycle conditions shift the maximum value of C5+ selectivity in... 

Theoretical calculations share with gas-phase kinetic and thermodynamic measurements the common aim of the understanding of the intrinsic reactivity properties of heteroaromatic compounds. The purpose of this subsection is to consider the predictive value of theoretical methods insofar as ionic substitution reactions on simple heteroaromatics are concerned. The topic under discussion is inherently limited by the wide range of interest in the understanding of the principles of these processes in solution. It is exactly in this field that an appropriate amount of data concerning gas-phase structural and reactivity properties of heteroaromatic compounds is at present available from modern experimental techniques that can be tested against theoretical predictions. 

For these general and commonly occurring POMs, ion pairing studies that focus primarily on structural and static POM properties are addressed first, followed by ones that encompass both structural and reactivity properties. 

J. S. Murray, P. C. Redfern, P. Lane, P. Politzer, and R. L. Wilier, /. Mol. Struct. (THEO-CHEM), 207, 177 (1990). A Computational Study of Structural and Reactive Properties of Imidazolidine, Piperazine, and Their N,N-Dinitro Derivatives. 

The copper enzymes covered in this article span a wide range in terms of both their structural and reactivity properties. Yet the copper centers in each share similar coordination geometries and have been designated Type... 

The chemical biology of nitric oxide (NO) and its derivatives rely heavily on the interaction of this diatom with heme and nonheme iron enzymes. Such interactions are important in the mammalian cardiovascular system as well as in the detoxification of NO in pathogenic microbes. As such, synthetic bioinorganic chemists have designed and constructed a variety of low molecular weight coordination complexes to understand the structural and reactive properties of FeNO systems as they relate to biological processes. Over the last several years, much synthetic work has focused on the construction of FeNO and FeNO complexes as representative models of NO reductase enzymes and as potential nitroxyl- or FINO-releasing molecules for new cardiovascular therapeutics. This review describes the synthesis, structure, spectroscopy, and reactivity of such FeNO systems published from 2011 to 2014. 

In summary, the Raman studies have provided a deeper understanding of the molecular structure and reactivity properties of bulk metal oxide catalysts during selective oxidation reactions. However, the fundamental insights have primarily been limited to the bulk properties of the bulk metal oxide catalysts. In order to obtain surface information about metal oxide catalysts with Raman spectroscopy (essentially a bulk characterization technique), it is necessary to look at chemisorbed species on the surface of bulk metal oxides (see Sec. VIII) or highly dispersed metal oxide systems such as supported metal oxide catalysts. 

Orthopthalaldehyde (OPA), which was introduced as a less-toxic alternative to ethylene oxide and glutaraldehyde, is less extensively studied than other commonly used medical sterUizing agents. However, a 2005 study of risks to healthcare workers from these exposures noted that OPA has similar structural and reactive properties to glutaraldehyde and acted similarly as a chemical sensitizer. OPA does not currently have a recommended exposure limit. A 2010 Johnson Johnson SDS for an OPA product reflected reproductive effects as unknown. 

The recognition that the mode of electron delocalization depends on the identity of an atom sets up the stage for a differentiation between structural and reactivity properties expected from organic and inorganic molecules. This point is illustrated by diverse applications and reference to existing experimental and computational data. The article itself can be viewed as a first step towards a reexamination of solid state physics phenomena (most notably conductivity and superconductivity) from a chemist s vantage point after it has been demonstrated that a self-consistent, qualitative understanding of molecular electronics across the Periodic Table is now at hand. 

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