Halogenation

In chemistry, halogenation is a chemical reaction which introduces one or more halogens into a chemical compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs.^[1] This kind of conversion is in fact so common that a comprehensive overview is challenging. This article mainly deals with halogenation using elemental halogens (F₂, Cl₂, Br₂, I₂). Halides are also commonly introduced using salts of the halides and halogen acids.^{[clarification needed]} Many specialized reagents exist for and introducing halogens into diverse substrates, e.g. thionyl chloride.