A number of polyfluoroindenylcations has been generated by the interaction of polyfluoroindenes with SbF5. In particular perfluoro-2-methylindenyl cation has been generated from perfluoro-2-methylindene (“open-chain” perfluoro-2-indenylmethyl ion has not been fixed). On this basis it has been proposed, that perfluoro-2-methylindenyl cation has an aromatic character (according to the Dewar and Breslow's