Acyl Halide
Molecules containing the functional group R-C(O)-X where the carbonyl carbon is bonded to a halide such as F, Cl, Br, or I. Can be formed from carboxylic acids with thionyl chloride SOCl2. Acyl halides readily undergo nucleophilic acyl substitution and can be converted into anhydrides, esters, amides, and carboxylic acids.