The trichloromethyl group is a functional group that has the formula −CCl3. The naming of is group is derived from the methyl group (which has the formula −CH3), by replacing each hydrogen atom by a chlorine atom. Compounds with this group are a subclass of the organochlorines. Some notable examples of compounds with this group are trichloromethane H−CCl3, 1,1,1-trichloroethane H3C−CCl3, and chloral HOC−CCl3.
The trichloromethyl group has a significant electronegativity.[ citation needed ] For this reason, trichloromethyl-substituted acids, such as trichloromethanesulfonic acid, are often stronger than the original. For example, the acidity constant (pKa) of trichloroacetic acid HOOC–CCl
3 is 0.77, whereas that of acetic acid is 4.76. [1] [2]
By the same principle, the trichloromethyl group generally lowers the basicity of organic compounds, e.g. trichloroethanol.
