Abstract: The four samples with varying water content were kept in double layer plastic bag. The intensity data up toS (H²+K²+L²)=384 were collected on a 12kW powerful rotating anode X-Ray diffraotometer in step scan mode. The coordinates and occupancy factors of sodium ions and water molecules were determined by F₀ and △F syntheses. The structure was refined by least-square method. The values of R were below 0.16. The bond lengths and bond angles derived from coordinates fell in normal ranges.
This study has shown the following results. On removal of water molecules, sodium ions in superoages migrate toward β cages and hexagonal prisms. In addition, sodium-water interactions decrease and sodium-oxygen interactions increase in dehydration process.