Phenyl(trichloromethyl)mercury is an organomercury compound with the formula C6H5HgCCl3.

Strong nucleophiles may catalyze the reaction by displacing CCl−3 from mercury, although the free ion is not believed to form in the process.

Unusually, the pure organomercury compound reacts with electron-poor alkenes, converting tetrachloroethylene to hexachlorocyclopropane:[1] The compound is prepared by treating phenylmercuric chloride [fi] with sources of dichlorocarbene.

These include the base/haloform reaction and thermolysis of sodium trichloroacetate:[2][3] Closely related compounds include phenyl(bromodichloromethyl)mercury (CAS registry number 3294-58-4) and phenyl(tribromomethyl)mercury (CAS registry number 3294-60-8).

[4] According to X-ray crystallography, the former has nearly linear coordination geometry at mercury, with a C-Hg-C angle of 179° and Hg-C distances of 2.047 Å.