Ronald Gillespie conducted highly original work on the reactions which occur, and the species which are formed, in strong acid media. In his classical work on the sulphuric acid solvent system, he demonstrated the ways in which simple physico–chemical techniques (especially cryoscopy) could be used to obtain new and fundamental information on the nature of dissolved organic and inorganic substances. In recent years, this work has developed into a study of even more highly acidic systems (for example, fluorosulfuric acid) now commonly called the ‘super-acid’ media, and this has led directly to the characterisation of new families of compounds (notably of sulfur, the halogens, selenium, tellurium, krypton and xenon) which often contain polyatomic cations, which has not been recognised in other media. New carbonium ion species have also been prepared and studied in these liquids.
Professor Ronald Gillespie FRS died on 26 February 2021.
