Bases concepts

R. G. Pearson, J. Am. Chem. Soc. 85 3533 (1963) T. L. Ho, Hard and Soft Acids and Bases in Organic Chemistry, Academic Press, New York, 1977 W. B. Jensen, The Lewis Acid-Base Concept, Wiley-Interscience, New York, 1980, Chapter 8. 

The strength of the complexation is a function of both the donor atom and the metal ion. The solvent medium is also an important factor because solvent molecules that are potential electron donors can compete for the Lewis acid. Qualitative predictions about the strength of donor-acceptor complexation can be made on the basis of the hard-soft-acid-base concept (see Section 1.2.3). The better matched the donor and acceptor, the stronger is the complexation. Scheme 4.3 gives an ordering of hardness and softness for some neutral and ionic Lewis acids and bases. 

The subject is also closely related to fuel-ash corrosion which in most cases is caused by a layer of fused salts such as sulphates and chlorides Attention has been focused on the electrochemistry of this type of corrosion and the relevant thermodynamic data summarised in the form of diagrams . Fluxing and descaling reactions also resemble in some respects reactions occurring during the corrosion of metals in fused salts. A review of some of the more basic concepts underlying corrosion by fused salts (such as acid-base concepts and corrosion diagrams) has appeared. ... 

We see in Table 11-IV that the equilibrium view of acid strengths suggests that we regard water itself as a weak acid. It can release hydrogen ions and the extent to which it does so is indicated in its equilibrium constant, just as for the other acids. We shall see that this type of comparison, stimulated by our equilibrium considerations, leads us to a valuable generalization of the acid-base concept. 

The dissolution of A1C13 in the NaAlCl4 melt makes the melt acidic. The acidic-base concept has been discussed by Blander et al. [40]. An acidic melt influences the solubility of the nickel chloride in the ZEBRA cell the solubility of the nickel chloride increases. 

For a monograph on Lewis acid-base theory, see Jensen, W.B. The Lewis Acid-Base Concept Wiley NY, 1980. For a discussion of the definitions of Lewis acid and base, see Jensen, W.B. Chem. Rev, 1978, 78, 1. 

W. B. Jensen, The Lewis Acid-Base Concepts, An Overview, John Wiley Sons, Hoboken, NJ, 1980. 

C21-0089. The fluorides BF3, AIF3, SiFq, and PF5 are Lewis acids. They all form very stable fluoroanions when treated with lithium fluoride. In contrast, three other fluorides, CF4, NF3, and SFg, do not react with lithium fluoride. Use Lewis acid-base concepts to explain this behavior. 

This theory was a milestone in the development of acid-base concepts it was the first to define acids and bases in terms other than that of a reaction between them and the first to give quantitative descriptions. However, the theory of Arrhenius is far more narrow than both its predecessors and its successors and, indeed, it is the most restrictive of all acid-base theories. 

The Lux-Flood theory relates to oxide melts. Geologists have often used acid-base concepts for the empirical classification of igneous silicate rocks (Read, 1948). Silica is implicitly assumed to be responsible for acidity, and the silica content of a rock is used as a measure of its acid-base balance ... 

The relative ease with which proton transfer is accomplished is responsible for the importance of the generalized acid-base concept in solution chemistry. The Br0nsted concept of acidity is most useful in this respect. Br0nsted defined an acid as a species that tends to give up a proton and a base as a species that tends to accept a proton. In this sense any proton transfer process having the general form... 

The HSAB concept is the hard-soft acid-base concept. 

Resonance such as (5.28a)-(5.28c) is inherently a quantal phenomenon, with no classical counterpart. In NBO language, each of the resonance interactions (5.28a)-(5.28c) corresponds to a donor-acceptor interaction between a nominally filled (donor Lewis-type) and unfilled (acceptor non-Lewis-type) orbital, the orbital counterpart of G. N. Lewis s general acid-base concept. As mentioned above, Lewis and Werner (among others) had well recognized the presence of such valence-like forces in the dative or coordinative binding of free molecular species. Thus, the advent of quantum mechanics and Pauling s resonance theory served to secure and justify chemical concepts that had previously been established on the basis of compelling chemical evidence. 

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