Acid-base chemistry Lewis

Lewis made additional valuable contributions to the theory of colored substances, radiation, relativity, the separation of isotopes, heavy water, photochemistry, phosphorescence, and fluorescence. As a major in the U.S. Army Chemical Warfare Service during World War I, he worked on defense systems against poison gases. From 1922 to 1935 he was nominated numerous times for the Nobel Prize in chemistry. Lewis s death, while measuring the dielectric constant of hydrogen cyanide on March 23, 1946, precluded his receiving the prize, which is not awarded posthumously, see also Acid-Base Chemistry Lewis Structures. 

C21-0040. Describe in detail the bonding in AI2 Clg. Explain the formation of the molecule in terms of Lewis acid-base chemistry. 

Up to this point, we have dealt with the subject of acid-base chemistry in terms of proton transfer. If we seek to learn what it is that makes NH3 a base that can accept a proton, we find that it is because there is an unshared pair of electrons on the nitrogen atom where the proton can attach. Conversely, it is the fact that the hydrogen ion seeks a center of negative charge that makes it leave an acid such as HC1 and attach to the ammonia molecule. In other words, it is the presence of an unshared pair of electrons on the base that results in proton transfer. Sometimes known as the electronic theory of acids and bases, this shows that the essential characteristics of acids and bases do not always depend on the transfer of a proton. This approach to acid-base chemistry was first developed by G. N. Lewis in the 1920s. 

Lewis acid-base chemistry provides one of the most useful tools ever devised for systematizing an enormous number of chemical reactions. Because the behavior of a substance as an acid or a base has nothing to do with proton transfer, many other types of reactions can be considered as acid-base reactions. For example,... 

Luder, W. F., and Zuffanti, S. (1946). The Electronic Theory of Acids and Bases. Wiley, New York. A small book that is a classic in Lewis acid-base chemistry. Also available as a reprint volume from Dover. 

The identification given by Equation 2.6 is consistent with the hard and soft acids and bases principle [12,15-21] established originally by Pearson [22] to explain many aspects of Lewis acid-base chemistry. 

The rational design of chelating agents as antidotes requires a careful consideration of acid-base chemistry. Metal ions are Lewis acids, while the chelating agents or ligands are Lewis bases. The concepts of hardness and softness may be used to describe systematically the interaction between them. A hard metal cation is one that retains its... 

An example of the different points of view and different tastes in the matter of acid-base definitions was provided to one of the authors in graduate school while attending lectures on acid-base chemistry from two professors. One Felt that the solvent system was very useful, but that the Lewis concept went too far because it included coordination chemistry. The second used Lewis concepts in all of his work, but felt uncomfortable with the Usanovich definition because it included redox chemistry To the latter s credit, however, he realized that the separation was an artificial one, and he suggested the pyridine oxide example given above. 

For most aqueous acid-base chemistry, the Lewis definitions are too general and lack the symmetry of the acid-conjugate base relationship. We will mostly use the Bronsted-Lowry definitions. 

Refs. [i] Finston H, Rychtman AC (1982) A new view of current acid-base theories. Wiley, New York [ii] Hand CW, BlewittHL (1986) Acid-base chemistry. Macmillan, New York [iii] )ensen WB (1980) The Lewis acid-base concepts. Wiley, New York [iv] Tanabe K (1989) New solid acids and bases. Elsevier, Amsterdam... 

In a Lewis acid-base reaction, a Lewis base donates an electron pair to a Lewis acid. Most of the reactions in organic chemistry involving movement of electron pairs can be classified as Lewis acid-base reactions. Lewis acid-base reactions illustrate a general pattern of reactivity in organic chemistry. 

A very useful book discussing many aspects of acid-base chemistry in terms of the Lewis definition is Jensen, W. B. The Lewis Acid-Base Cnncept.s An Overview. Wiley New York, 1980. 

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