Lewisaciditet

Lewisaciditet is a concept in chemistry that describes the ability of a chemical species to accept an electron pair. This acceptance of an electron pair forms a coordinate covalent bond. Lewis acids are therefore electron-pair acceptors. The concept was introduced by Gilbert N. Lewis in 1923. In contrast to Brønsted-Lowry acids, which are proton donors, Lewis acids do not necessarily involve protons. Common examples of Lewis acids include metal ions such as Al³⁺, Fe³⁺, and Zn²⁺, as well as electron-deficient molecules like BF₃ and AlCl₃. Lewis acids typically have an incomplete octet of valence electrons or can expand their octet to accommodate the electron pair. The strength of a Lewis acid is determined by its tendency to accept an electron pair, which is influenced by factors such as electronegativity, steric hindrance, and the electronic configuration of the species. The interaction between a Lewis acid and a Lewis base, an electron-pair donor, is known as Lewis acid-base adduct formation. This concept is fundamental to understanding various chemical reactions, including organic synthesis, coordination chemistry, and catalysis.