Reactions in the SbF5/HF/PF3 system: a DFT and ab initio study

Reactions SbF5+nHF+PF3 (n=1,2) have been investigated using ab initio and DFT methods. This work was motivated by the recent experimental study of Seppelt and co-workers [Inorg. Chem. 39 (2000) 2784] who obtained new salt PF3H+·SbF6−·HF as a product for n=2. The calculated gas-phase cluster, HPF4·SbF5–HF, resembles the solid state ion pair in geometry and charge distribution. We have also found a low-barrier isomerization between the equivalent structures of the distinct cluster, HPF4–HF·SbF5. It is suggested that this isomerization mechanism may be responsible for the exchange of the F atoms indicated for the SbF5/HF/PF3 system in HF solution [loc. cit].