Methyl mercury
Methylmercury (sometimes methyl mercury) is an organometallic cation with the formula [CH3Hg]+. It is a bioaccumulative environmental toxicant.
"Methylmercury" is a shorthand for "monomethylmercury", and is more correctly "monomethylmercury(II) cation". It is composed of a methyl group (CH3-) bonded to a mercury ion; its chemical formula is CH3Hg+ (sometimes written as MeHg+).
As a positively charged ion it readily combines with anions such as chloride (Cl−), hydroxide (OH−) and nitrate (NO3−). It also has very high affinity for sulfur-containing anions, particularly the thiol (-SH) groups on the amino acid cysteine and hence in proteins containing cysteine, forming a covalent bond. More than one cysteine moiety may coordinate with methylmercury, and methylmercury may migrate to other metal-binding sites in proteins.
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