SN2, or bimolecular nucleophilic substitution, is a type of chemical reaction where a nucleophile attacks an electrophile, leading to the replacement of a leaving group. In this process, two molecules interact simultaneously, hence the "bi" in bimolecular. The nucleophile, which is often a negatively charged ion or a molecule with a lone pair of electrons, approaches the electrophile, typically a carbon atom bonded to a leaving group, such as a halide like chlorine or bromine. During the SN2 reaction, the nucleophile forms a bond with the carbon atom while the leaving group departs. This results in an inversion of configuration at the carbon center, which is crucial for stereochemistry. SN2 reactions are favored in primary and some secondary substrates,