<p> Techniques have been developed for making cryoscopic and vapour pressure measurements in anhydrous hydrogen fluoride. The cryoscopic constant for the solvent has been determined. </p> <p> The techniques developed have been used to determine the mode and extent of the ionization of some acids and bases of the HF system. The formation and stability of polymeric ions in the solvent has been investigated and the formation of the previously unknown anion As₂F₁₁⁻ has been shown. Cryoscopy has been used to detect a new polymeric 1:1 adduct of XeF₂ and SbF₅. Solutions of cyanides in HF have been investigated and the formation of a new polymeric cation Hg₂CN₃⁺, formed when mercury cyanide dissolves in HF, has been suggested. The results of some experiments on solvolysis reactions are also reported. </p> / Thesis / Doctor of Philosophy (PhD)

<p> The cryoscopic constant for fluorosulphuric acid has been determined and the nature and concentration of the impurities in the solvent have been investigated.</p> <p> The NMR and Gouy methods have been used to determine the magnetic susceptibility of solutions of iodine fluorosulphates. The NMR method has been shown to lead to spurious results.</p> <p> Cryoscopy, conductivity and UV and visual spectrophotometry have been used to elucidate the state of iodine fluorosulphates in fluorosulphuric acid. Solutions of stoichiometry corresponding to fifth-, third-, half-, uni-, tri-, and hepta-valent iodine have been investigated. The highest valence state observed was that of iodine trifluorosulphate which has been shown to be an acid in fluorosulphuric acid. Measurements on fifth- and third-valent iodine solutions indicate that I5+ and I3+ are formed. Measurements on half- and univalent iodine solutions suggest that I2+ is formed. The observed magnetic moment of this species agrees well with that required by theory, 2.0 BM.</p> / Thesis / Doctor of Philosophy (PhD)