organohalogens

Organohalogens are organic compounds containing one or more halogen atoms—fluorine, chlorine, bromine, or iodine—covalently bonded to carbon. They cover a broad range from simple alkyl and aryl halides to complex polymers and natural products. The halogens influence reactivity, polarity, and stability, often making the compounds more inert and persistent.

Classification includes alkyl and alkenyl halides, aryl halides, and specialized groups such as organofluorines, organochlorines, organobromines, and organoiodines. Fluorinated compounds like polytetrafluoroethylene are highly inert and used in coatings and electronics; chlorinated solvents (chloroform, dichloromethane) and PCBs are classic organochlorines. Organobromines appear in flame retardants; organoiodines occur in some pharmaceuticals.

Synthesis typically forms C–X bonds by halogenation, nucleophilic substitution on haloalkanes, or electrophilic aromatic substitution. Properties vary: fluorinated organohalogens are highly stable; chlorinated and brominated species can be reactive but may persist in the environment.

Applications span solvents, refrigerants, polymers, pesticides, and medicines. Many organohalogens raise environmental and health concerns due to persistence and toxicity; notable examples include PCBs, DDT, and PFAS. Regulation aims to reduce releases and limit or ban problematic compounds to mitigate ecological and human health impacts.