||This thesis describes the use of pulsed-gradient spin-echo (PGSE) NMR techniques to investigate the symmetry and structure of halonium ions in super acid environments. To this end, PGSE NMR methods were developed and implemented, beginning with simple chemical mixtures and moving to halonium ion in super acid environments. Computational data were also generated to determine the approximate molecular radii of some of the molecules used in the PGSE study. Several discrepancies emerged during method development and were investigated. These discrepancies include the difference between the diffusion coefficient of methyl hydrogens and alcoholic hydrogens found on the same molecule of methanol.