The determination of the acidity of super-acid media by dynamic nuclear magnetic resonance measurements: the system fluorosulphuric acid–antimony pentafluoride

Abstract

N.m.r. measurements of the lifetime of the oxonium ion in mixtures of fluorosulphuric acid and antimony pentafluoride are used to derive relative acidities of media containing between 14 and 82 mol % of SbF₅. The acidity increases monotonically up to at least 80 mol % SbF₅. The assumptions underlying the method are critically examined.