Ethylmercury

Ethylmercury (sometimes ethyl mercury) is a cation composed of an ethyl group and a mercury atom; its chemical formula is C2H5Hg+. The term 'ethylmercury' is sometimes used as a generic term to describe organomercury compounds which include ethylmercury such as ethylmercury chloride and ethylmercury urea. The CAS registry number for ethylmercury chloride is.

Ethylmercury is one of the metabolites of thiomersal, which is used as a preservative in some vaccines. For this application, the ethylmercury salt sodium ethylmercuric thiosalicylate is used. Thiomersal (C9H9HgNaO2S) is made from the combination of ethyl mercuric chloride, thiosalicylic acid, sodium hydroxide and ethanol.

Unlike methylmercury, ethylmercury has not been found to bioaccumulate. The toxicity of ethylmercury is not well studied, but exposure standards based on methylmercury (such as those currently recommended by the EPA) are not demonstrated to be equivalent for ethylmercury.