Lewis theory inorganic chemistry

Lewis Definition of Acids and Bases An even more generalised theory of acids and bases was put forward by Lewis. According to Lewis definition an acid is a substance that can accept an electron pair to form a covalent bond and base is a substance that can furnish an electron pair to form a covalent bond. In other words, an acid is an electron pair Inorganic Chemistry... 

Electron donation-acceptance reactions, which are considered to be Lewis acid-base interactions, also include the formation of coordination compounds, complex formation through hydrogen bonding, charge transfer complex formation, and so on. It should be apparent that the Lewis theory of acids and bases encompasses a great deal of both inorganic and organic chemistry. 

The chemistry of coordination compounds is a broad area of inorganic chemistry that has as its central theme the formation of coordinate bonds. A coordinate bond is one in which both of the electrons used to form the bond come from one of the atoms, rather than each atom contributing an electron to the bonding pair, particularly between metal atoms or ions and electron pair donors. Electron pair donation and acceptance result in the formation of a coordinate bond according to the Lewis acid-base theory (see Chapter 5). However, compounds such as H3N BC13 will not be considered as coordination compounds, even though a coordinate bond is present. The term molecular compound or adduct is appropriately used to describe these complexes that are formed by interaction of molecular Lewis acids and bases. The generally accepted use of the term coordination compound or coordination complex refers to the assembly that results when a metal ion or atom accepts pairs of electrons from a certain number of molecules or ions. Such assemblies commonly involve a transition metal, but there is no reason to restrict the term in that way because nontransition metals (Al3+, Be2+, etc.) also form coordination compounds. 

Fig. 2.18 Alfred Werner (1866-1919) is usually described as the founder of coordination chemistry. Werner did his Ph.D. in 1889 with Professor Arthur Hantzsch and, after spending one semester with Marcellin Berthelot at the College de France at Paris, returned to the ETH at Zurich to finish his Habilitation in 1892. One year later, he became Associate Professor at the University of Zurich and was promoted as Professor of Chemistry in 1895. Remarkably, despite the widespread attention for his groundbreaking coordination theory, he was not permitted to give the basic lecture in inorganic chemistry before 1902. Werner attracted students from all over the world, supervised 230 Ph.D. theses and was the first Swiss to receive the Nobel Prize for Chemistry in 1913. In his famous book Valence and the Structure of Atoms and Molecules , published in 1923, Gilbert N. Lewis wrote ...in attempting to clarify the fundamental ideas of valence, there is no work to which I feel so much personal indebtedness as to this of Werner s (photo from Helv. Chim. Acta 75, 21-61 (1992) reproduced with permission of Dr. Kisaktirek, Editor of Helvetica Chimica Acta)...

Nobody will argue the importance of the idea of the electron pair bond, introduced by Lewis [67], in chemistry. Together with the Bohr theory of the electronic structure of the atom [68] and its connection with the periodic system [69], one has the ingredients for a true chemical theory. The octet model introduced by Langmuir [70] soon demonstrated its immense explanative power for organic and inorganic structure alike. 

Modified Lewis theory . Chemistry Education Research and Practice, 2001, Vol. 2, pp. 67-72 (Part 1), 179-182 (Part 2) [http /www.uoi.gr/cerp] Recent Research Developments in Inorganic Chemistry, 2004, Vol. 4, pp. 1-11. 

Lewis published these ideas in his 1923 book Valence and the Structure of Atoms and Molecules, and they were widely taken up and developed in the U.S.A. and Europe, for example, by N. V. Sidgwick at Oxford, whose Electronic Theory of Valency appeared in 1927. The Nobel Prize in Chemistry was left unfilled in 1919, 1924 and 1933 for lack of candidates of suitable stature, and Lewis would have been an appropriate candidate for any of these years. In fact, he was nominated for a Nobel Prize by the inorganic chemist and historian of chemistry, J. R. Partington (1886-1965) at the University of London. For the first half-century after the award of the first Nobel Prize in Chemistry to van t Hoff in 1901, the chemistry prize went to those who had discovered or characterised new chemical elements, new physico-chemical principles, new chemical reactions, or had elucidated the structure and accomplished the synthesis of natural products. The first award for research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances went in 1954 to Linus Pauling at Caltech. 

The solidly built organic chemistry mechanisms used the contemporary (in the 1920s) notion of electronic duplet and the ideas of nucleophilicity and electrophilicity, among others. A completely different arrangement of concepts comes out of the more recently developed inorganic reaction mechanisms, where the electronic situation is usually more complicated, and concepts like ligand field theory, Lewis acidity, hardness, etc. appear. 

Applying Lewis acid-base theory to inorganic and organic chemistry to identify the role of the reacting species... 

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