INVESTIGATIONS OF STRUCTURE AND PROTONIC CONDUCTIVITY IN COMPOSITES OF HYDROUS ANTIMONY(V) OXIDE AND MORDENITE

Composites prepared by hydrolysis of antimony pentachloride in the pre sence of the zeolite mordenite have been characterised by X-ray powder diffractometry (XRD), Si-29 and Al-27 MAS NMR, Sb-121 Mossbauer spect roscopy and investigations of ac conductivity as a function of relativ e humidity (RH). Both XRD and MAS NMR studies show degradation of the zeolite framework, the extent of the damage depending upon the amount of antimony pentachloride used in the preparation. Mossbauer spectra a re consistent with the antimony-containing component being amorphous a ntimonic acid, as anticipated from the preparative conditions. The com posites are protonic (H+) conductors, but do not show the enhanced con ductivities characteristic of 'tin mordenites', which show the same di sruption of the zeolite framework.