Electrophilism

Electrophilism is a chemical concept describing the tendency of a chemical species, known as an electrophile, to react with electron-rich regions of other molecules. Electrophiles are characterized by being electron-deficient, meaning they possess a positive partial charge or a complete positive charge, or they have an incomplete octet of valence electrons. This electron deficiency drives their attraction to areas of high electron density.

Common examples of electrophiles include positively charged ions such as H+ or Br+, molecules with polar double or triple bonds where one atom carries a partial positive charge (like the carbon in a carbonyl group), and neutral molecules that can accept a pair of electrons to complete an octet, such as Lewis acids like BF3 or AlCl3.

The interaction between an electrophile and an electron-rich site, often called a nucleophile, is fundamental to many organic and inorganic chemical reactions. This interaction typically involves the formation of a new covalent bond, where the nucleophile donates electrons to the electrophile. This process is a cornerstone of reaction mechanisms, including electrophilic addition, electrophilic substitution, and various polymerization reactions. The strength of electrophilism is often quantified by experimental or theoretical methods, influencing reaction rates and selectivities.