Resolving sites of occupancy of tetramethylammonium ions in zeolites using 13C n.m.r. spectroscopy

Abstract
Isotropic 13C n.m.r. chemical shifts distinguish between tetramethylammonium ions trapped in the α and β cages of the zeolite A structure and are insensitive to Si:Al ratio; the observed intensities indicate near complete occupancy of the β cage over the complete composition range.