TOWARD PILLARED METAL SULFIDES - ENCAPSULATION AND RIETVELD STRUCTURAL CHARACTERIZATION OF THE AL13O4(OH)(24)(H2O)(12)(7+) CLUSTER IN MOS2 AND WS2

The synthesis of [Al13O4(OH)(24)(H2O)(12)](x)MS2 (x = 0.02-0.05, M = M o; x = 0.02-0.055, M = W) was accomplished by a precipitative encapsul ation technique using single layers of MS2. The products were characte rized by powder X-ray diffraction, energy dispersive spectroscopy (EDS ), thermal gravimetric analysis (TGA), Al-27 MAS-NMR, room temperature electrical conductivity measurements, and surface area measurements. Powder X-ray diffraction patterns show ism expansion of approximately 9.9 Angstrom Al-27 MAS-NMR indicates that the cluster is intact betwee n the MS2 layers. One-dimensional electron density mapping and Rietvel d refinement performed on the powder diffraction data show that the cl uster is oriented with its C-3 symmetry axis perpendicular to the laye rs, The samples exhibit conductivity values from 3 to 14 S/cm, TGA sho ws that the cluster is completely stable to 100 degrees C, and largely stable to 330 degrees C, Surface area measurements suggest that the s pace between the clusters is not accessible. (C) 1998 Academic Press.