AB-INITIO STRUCTURE SOLUTION FROM X-RAY-POWDER DATA AT MODERATE RESOLUTION - CRYSTAL-STRUCTURE OF A MICROPOROUS LAYER SILICATE

The ab initio crystal structure solution of a layer silicate is presen ted. Since the crystallinity of the material is limited, the correspon ding X-ray powder pattern shows only moderate resolution. Based on a n ew interpretation of the tangent formula, a general direct method stra tegy for the determination of the crystal structure of poorly crystall ine materials from X-ray powder patterns is presented. The structure m odel derived from the interpretation of the E map was subsequently ref ined with the Rietveld technique using the whole diffraction pattern. This leads finally to a picture of the crystal structure of atomic res olution which explains in full detail the specific characteristics of the material.