NEW STRUCTURES - NEW INSIGHTS - PROGRESS IN STRUCTURE-ANALYSIS OF NANOPOROUS MATERIALS

In the recent past structure determination of microporous materials ha s experienced considerable developments in methodology. The FOCUS meth od: high resolution powder diffraction data used for direct method str ucture solution in combination with crystal chemistry based modelling. The models are retrieved from electron density maps calculated in dir ect method runs, energy minimized and checked through for realistic an gles and distances values. The SUM-TF method: diffraction patterns at moderate resolution analysed with direct methods using a modified tang ent formula which includes Patterson information for the structure sol ving. In this way the atomic resolution criterion for direct methods i s bypassed. This overview gives a summary of the structures successful ly solved using these new techniques. (C) 1998 Elsevier Science B.V. A ll rights reserved.