1. 1 Structure solution from (high pressure) powder diffraction data Yaroslav Filinchuk SNBL @ ESRF www.filinchuk.com www.snbl.eu Erice, 4 – 14 June 2009 workshop preview

2. 2 Powder diffraction with a 2D detector Problems of powder diffraction Keep this picture in mind when using 1D detectors Y. Filinchuk Erice, 4-14 June 2009

3. 3 Powder diffraction: needs and posibilities … this was the case of a simple structure and good data to identify a phase to attribute data to a known structure type (indexing suffice) to refine a known structure to solve it from scratch (ab initio structure solution) to observe T or P-variation to monitor a chemical reaction (time resolution) Combination of all Combination of all: new phases, transitions, evolution… Data can be good or bad, or in between... Y. Filinchuk Erice, 4-14 June 2009

4. 4 Essential programs Fullprof Winplotr  Fullprof: Rietveld refinement, simulation of powder data, data manipulation and program shell (Winplotr) Dicvol, Chekcell  Dicvol, Chekcell: indexing rearch for the true cell FOX  FOX: structure solution in the direct space (“trial and errror”)  PowderCell  PowderCell: generation of sub- and superstructures Platon  Platon: search for a true symmetry, for voids, “problems” Mercury, Diamond  Mercury, Diamond: visualization, analysis of coordination polyhedra, ineratomic distances, topology  Databases  Databases: International Tables (Vol. А), ICDD, ICSD, … Y. Filinchuk Erice, 4-14 June 2009

5. 5 Problems tackled indexing structure solution from “bad” powder data using chemical knowledge in solving structures dealing with severe texture during structure solution finding higher metric or crystallographic symmetry refinement by the Rietveld method Y. Filinchuk Erice, 4-14 June 2009