trichloro

Trichloro is a chemist's prefix used in the names of organic compounds to indicate that three chlorine atoms replace hydrogen atoms in a molecule. The prefix appears in a variety of contexts, from simple alkyl groups bearing three chlorines to more complex ring systems. It is not a substance in itself, but a descriptor in systematic nomenclature.

Common examples include trichloroacetic acid (three chlorine atoms attached to the acetic acid skeleton), trichloroethylene (a chlorinated hydrocarbon solvent), and 1,1,1-trichloroethane (a saturated chlorinated solvent formerly used in cleaning and manufacturing).

In IUPAC naming, 'trichloro' indicates three chlorine substituents; the position numbers are given for each substituent. The chemical's properties depend on the parent skeleton; trichloro substitutions typically increase acidity or polarity and alter reactivity; many trichloro compounds are fairly dense and volatile.

Environmental and health notes: many trichloro compounds persist in the environment and can be toxic or carcinogenic; trichloroethylene has been linked to cancer risk and is subject to regulatory controls; 1,1,1-trichloroethane has been phased out in many regions due to ozone depletion potential; safe handling and disposal are emphasized.

See also chlorinated hydrocarbons and organochlorine compounds.