Lewis acid/base basic behaviour

The other well-used definitions of acidic and basic behaviour are those of G. N. Lewis. He proposed that an acid is an electron-pair acceptor and a base is an electron-pair donor. The Lewis definitions are not used in this text, but many metal fluorides, for example, behave as Lewis acids, e.g. SbFj + F" - SbFj,. In that case, the fluoride ion acts as a Lewis base and donates an electron pair to the Sb centre. 

Two definitions of acids and bases are used nowadays, the Bronsted definition and the Lewis definition. This book deals with the quantitative behaviour of Lewis bases. However, since Lewis bases are also Bronsted bases, this chapter begins with a short presentation of the Bronsted definition and of the quantitative behaviour of Bronsted bases [1]. The Lewis definition and the many ways for its quantification will then be studied. This introductory chapter is intended to help in the understanding and use of the tables in Chapters 2-6, which contain quantitative data on Lewis basicity and affinity, and not to discuss the Lewis acid/base concept in depth. This subject has been excellently treated in a book [2] and a review [3] by Jensen, and books and chapters by Mulliken and Person [4], Gur yanova et al. [5], Drago [6], Finston and Rychtman [7] and Weinhold and Landis [8], to quote just a few. 

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