We report a surprising chemical reactivity of gold nanoshells with carbon tetrachloride. Gold nanoshells are nanoparticles constructed from a silica core encapsulated in a gold shell. An aminoalkoxysilane linker molecule is used to derivatize the silica surface, which facilitates the attachment of the gold shell. Evidence is shown for the decomposition of the gold shell due to a reaction with carbon tetrachloride. The reaction is believed to proceed through the formation of a charge transfer complex between carbon tetrachloride and the gold-amine complex. The reaction is facilitated by the presence of defects in the shell layer.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.