Phenyl(trichloromethyl)mercury

Phenyl(trichloromethyl)mercury is an organomercury compound with the formula C₆H₅HgCCl₃. It is a white solid that is soluble in organic solvents. The compound is used as a source of dichlorocarbene, e.g. in cyclopropanation reactions, because the products are particularly easy to extract from the reaction mixture. 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]

C₆H₅HgCCl₃ → C₆H₅HgCl + CCl₂

CCl₂ + Cl₂C=CCl₂ → C₃Cl₆

Phenyl(trichloromethyl)mercury

Identifiers
CAS Number	3294-57-3 Y
3D model (JSmol)	Interactive image
ChemSpider	69255
EC Number	221-960-9
PubChem CID	76799
UNII	JH955G783H Y
InChI InChI=1S/C6H5.CCl3.Hg/c1-2-4-6-5-3-1;2-1(3)4;/h1-5H;; Key: MVIAEGXPYBMVPT-UHFFFAOYSA-N
SMILES C1=CC=C(C=C1)[Hg]C(Cl)(Cl)Cl
Properties
Chemical formula	C7H5Cl3Hg
Molar mass	396.06 g·mol−1
Appearance	white solid
Melting point	117–118 °C (243–244 °F; 390–391 K)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	toxicity
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H310, H330, H373, H410
Precautionary statements	P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P304+P340, P310, P314, P320, P321, P322, P330, P361, P363, P391, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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]

NaO₂CCCl₃ + C₆H₅HgCl → C₆H₅HgCCl₃ + NaCl + CO₂

Related compounds

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.^[5]

Also known is bis(trichloromethyl)mercury, Hg(CCl₃)₂.