Any member of the class of chlorobenzenes in which a benzene ring is substituted by five chloro groups.
| Member | Definition | Role |
|---|
| decachlorobiphenyl | A polychlorobiphenyl that is biphenyl in which all of the hydrogens are replaced by chlorines. | decachlorobiphenyl |
| pentachlorobenzene | A member of the class of pentachlorobenzenes that is benzene in which five of the hydrogens are replaced by chlorines. Now classed as a persistent organic pollutant under the Stockholm Convention. | pentachlorobenzene |
| pentachlorophenol | A chlorophenol that is phenol substituted by 5 chloro groups. | pentachlorophenol |
| quintozene | A C-nitro compound that is nitrobenzene in which every hydrogen has been replaced by a chlorine. A fungicide used on a variety of crops, including cotton, rice and seed grains, it is no longer approved for use within the European Union. | pentachloronitrobenzene |