Mercury(II) acetate

Mercury(II) acetate, also known as mercuric acetate is a chemical compound, the mercury(II) salt of acetic acid, with the formula Hg(O2CCH3)2. Commonly abbreviated Hg(OAc)2, this compound is employed as a reagent to generate organomercury compounds from unsaturated organic precursors. It is a white, water-soluble solid, but some samples can appear yellowish with time owing to decomposition.

Structure
Mercury(II) acetate is a crystalline solid consisting of isolated Hg(OAc)2 molecules with Hg-O distances of 2.07 Å. Three long, weak intermolecular Hg···O bonds of about 2.75 Å are also present, resulting in a slightly distorted square pyramidal coordination geometry at Hg.

Synthesis and reactions
Mercury(II) acetate can be produced by reaction of mercuric oxide with acetic acid.

HgO + 2 CH3COOH → Hg(CH3COO)2 + H2O

Inorganic reactions
Mercury(II) acetate in acetic acid solution reacts with H2S to rapidly precipitate the black (β) polymorph of HgS. With gentle heating of the slurry, the black solid converts to the red form. The mineral cinnabar is red HgS. The precipitation of HgS as well as a few other sulfides, using hydrogen sulfide is a step in qualitative inorganic analysis.

Organic chemistry
Electron-rich arenes undergo "mercuration" upon treatment with Hg(OAc)2. This behavior is illustrated with phenol:
 * C6H5OH + Hg(OAc)2 → C6H4(OH)-2-HgOAc + HOAc

The acetate group (OAc) that remains on mercury can be displaced by chloride:
 * C6H4(OH)-2-HgOAc + NaCl → C6H4(OH)-2-HgCl + NaOAc

The Hg2+ center binds to alkenes, inducing the addition of hydroxide and alkoxide. For example, treatment of methyl acrylate with mercuric acetate in methanol gives an α-mercuri ester:
 * Hg(OAc)2 + CH2=CHCO2CH3 + CH3OH →  CH3OCH2CH(HgOAc)CO2CH3 + HOAc

Exploiting the high affinity of mercury(II) for sulfur ligands, Hg(OAc)2 can be used as a reagent to deprotect thiol groups in organic synthesis. Similarly Hg(OAc)2 has been used to convert thiocarbonate esters into dithiocarbonates:
 * (RS)2C=S + H2O + Hg(OAc)2 → (RS)2C=O + HgS + 2 HOAc

Mercury(II) acetate is used for oxymercuration reactions.

A famous use of Hg(OAc)2 was in the synthesis of idoxuridine.

Toxicity
Mercuric acetate is a highly toxic compound, due to it being water-soluble and having mercury ions. Symptoms of mercury poisoning include peripheral neuropathy, skin discoloration and dequamation (peeling and/or shedding of the skin). Chronic exposure may cause reduced intelligence and kidney failure.