Structural characterization of the hydrous layer silicate Na-RUB-18, Na8Si32O64(OH)8•32H2O and derivatives with XPD-, NPD-, and SS NMR experiments

The structural characterization of hydrous layer silicates using X-ray- and neutron powder diffraction studies and complementary experiments with solid state NMR is presented for a variety of materials of the RUB-18 family. The parent Na-RUB-18 shows interesting temperature dependent proton dynamics and proton conduction which is studied with NMR and neutron diffraction experiments. The silicic acid H-RUB-18 crystallises without intercalate water and with considerable distortion of the original structure. Acetone and alanine intercalated in H-RUB-18 occupy the channel-like void of the interlayer space by re-arranging the original stacking motive upon uptake. The article is a summary on work on this family of materials presenting new results in perspective with results already available in the literature. (c) 2007 Elsevier Inc. All rights reserved.