What is "ethylmercury"

n. (context chemistry English) The organometallic cation CH₃CH₂Hg⁺; it is a toxicant that does not seem to accumulate in the environment

Ethylmercury (sometimes ethyl mercury) is a cation composed of an ethyl group bound to a mercury(II) centre; its chemical formula is CHHg. Ethylmercury is sometimes used as a generic term to describe organomercury compounds which include ethylmercury such as ethylmercury chloride and ethylmercury urea.

Ethylmercury is one of the metabolites of thiomersal, which is used as a preservative in some vaccines. Thiomersal is the ethylmercury-releasing compound sodium ethylmercuric thiosalicylate, CHHgNaOS.