Extraction of Crystal structural data of a number of chromate use complexes by of Rietveld equation and WinPLOTR program from powder diffraction patterns

Shahriar Ghammamy, Nazila Moha

Abstract

Tetraalkylammonium salts produced micro crystals that are not suitable for x-ray single crystal diffractions. Structural data can be extracted from powder diffraction patterns and by use of mathematical methods. The method used for this research based on Rietveld method to perform full matrix least-squares refinement of unit parameters from powder diffraction patterns. Powder Diffraction pattern of a number of chromate complexes were successfully analyzed by mathematical equations. The use of pattern-fitting techniques for the characterization of the microstructure is discussed through applications to nanocrystalline materials. We used direct space that need no powder pattern analysis and is based on global optimization of a structural model to improve agreement between the observed and calculated diffraction patterns. The extracted data compared with single crystal X-ray data and found good agreement between two kinds of data.