A chlorophenol is any organochloride of phenol that contains one or more covalently bonded chlorine atoms. Chlorophenols are produced by electrophilic halogenation of phenol with chlorine. Most chlorophenols have a number of different isomers. Monochlorophenols have three isomers because there is only one chlorine atom that can occupy one of three ring positions on the phenol molecule; 2-chlorophenol, for example, is the isomer that has a chlorine atom in the ortho position. Pentachlorophenol, by contrast, has only one isomer because all five available ring positions on the phenol are fully chlorinated.
Chlorophenols are commonly used as pesticides, herbicides, and disinfectants.