Perfluoroperhydro-indane,-fluorene,-acenaphthylene,-phenanthrene,-anthracene and- pyrene have been prepared, by fluorination of the aromatic hydrocarbons with cobaltic fluoride. When defluorinated in the vapour phase over heated metal gauze perfluoro-indane,- acenaphthylene,-acenaphthene,-anthracene and-pyrene were obtained.
