A trichlorophenol is any organochloride of phenol that contains three covalently bonded chlorine atoms.
Trichlorophenols are produced by electrophilic halogenation of phenol with chlorine.
[1] Different isomers of trichlorophenol exist according to which ring positions on the phenol contain chlorine atoms.
2,4,6-Trichlorophenol, for example, has two chlorine atoms in the ortho positions and one chlorine atom in the para position.
There are six different isomers: