Description:
<jats:p> The Brönsted-Lewis superacid HSO<jats:sub>3</jats:sub>F-SbF<jats:sub>5</jats:sub> or "magic acid" is re-investigated by modern <jats:sup>19</jats:sup>F NMR methods over a wide concentration range. The system is found to be considerably more complex than had been assumed previously. A total of 13 different anions are identified of which only five have previously been identified in magic acid. With increasing SbF<jats:sub>5</jats:sub> contents the concentration of monomeric anions like [SbF<jats:sub>6</jats:sub>]<jats:sup>-</jats:sup>, [SbF<jats:sub>5</jats:sub>(SO<jats:sub>3</jats:sub>F)]<jats:sup>-</jats:sup>, cis- and trans-[SbF<jats:sub>4</jats:sub>(SO<jats:sub>3</jats:sub>F)<jats:sub>2</jats:sub>]<jats:sup>-</jats:sup>, and mer-[SbF<jats:sub>3</jats:sub>(SO<jats:sub>3</jats:sub>F)<jats:sub>3</jats:sub>]<jats:sup>-</jats:sup> gradually decreases. Except for [Sb<jats:sub>2</jats:sub>F<jats:sub>11</jats:sub>]<jats:sup>-</jats:sup>, which is present in very small concentrations only, the formation of oligomers involves exclusively μ-fluorosulfato bridges. In addition to donor (SO<jats:sub>3</jats:sub>F)<jats:sup>-</jats:sup> and acceptor (SbF<jats:sub>5</jats:sub>) complex formation to give [SbF<jats:sub>5</jats:sub>(SO<jats:sub>3</jats:sub>F)]<jats:sup>-</jats:sup> and possibly ligand redistribution, the solvolysis of SbF<jats:sub>5</jats:sub> or SbF<jats:sub>4</jats:sub>(SO<jats:sub>3</jats:sub>F) in HSO<jats:sub>3</jats:sub>F appears to be the principal formation reaction for polyfluorosulfatofluoroantimonate(V) anions. In glass (NMR tubes) the solvolysis product HF is converted to the oxonium ion [H<jats:sub>3</jats:sub>O]<jats:sup>+</jats:sup>, which has previously been identified by <jats:sup>1</jats:sup>H NMR and structurally characterized as [H<jats:sub>3</jats:sub>O][Sb<jats:sub>2</jats:sub>F<jats:sub>11</jats:sub>] by us.Key words: magic acid, conjugate superacid, fluorosulfuric acid, <jats:sup>19</jats:sup>F NMR spectra. </jats:p>