17O MQMAS NMR studies of Na-A and Ca-AElectronic supplementary information (ESI) available: Fig. S1: schematic structure of zeolite A. Fig. S2: 17O 1-pulse spectra. Fig. S3: 17O MQMAS NMR spectra. Comparison of hydrated and dehydrated Na-A. See http://www.rsc.org/suppdata/cc/b2/b208356f/

Abstract

We report, for the first time, 17O MQMAS and 17O/23Na double resonance NMR studies on calcium-exchanged zeolite sodium-A; the results show that the isotropic shifts of the framework sites are strongly affected by factors including the hydration level and nature of the charge-balancing cations.