Meeting report

X-ray structure school

[X-ray school]
The second school on X-ray structural analyses ‘Analyse Structurale par Diffraction des Rayons X, Structures Absolues, Macles, Incommensurables’ was held in Toulouse, France, September 23-27, 2002, chaired by J.C. Daran (CNRS ,Toulouse) and C. Lecomte (U. Henri Poincaré and CNRS, Nancy). This school was sponsored by the CNRS, the French Ministry of the U. (Physics and Chemistry grants) and the French Assn of Crystallography (AFC, Assn Française de Cristallographie). It was also funded by different manufacturers, Alexandre Lab, Bruker-Nonius, Elexience, Oxford-Diffraction and Stoe.

Various topics were covered in the school, which was divided into two parts. The first part was devoted to the fundamental theory of crystallography, data collection , data reduction, structure solution, least-squares refinements and demonstration of the Cambridge Structural Database. The second part was related to some difficult problems as absolute structure determination, modulated structures and twinning. Practical work sessions concerning the structure solution computer programs (Shelxl, Crystals, SIR, MoPro) were organised as well as hands on sessions. Most lectures and all tutorials were taught using the French language.

Lecturers and topics included Direct and Reciprocal Space (N. Ghermani, France) Crystal Symmetry (H. Flack, Switzerland), Scattering and Structure Factors (C. Lecomte, France), Data Reduction (S. Pillet, France), From Punct to two Dimensional Detectors (M. Pierrot, France), Direct Methods (C. Giacovazzo, Italy), Patterson Analysis (J.P. Legros, France), New Developments in Direct Methods (H. Gornitzka, France). Incommensurate Structures (V. Petricek, Czech Republic), Least-Squares refinements (D. Watkin, UK), Introduction to twinning (S. Parsons, UK), Absolute Structure and Absolute Configuration (H. Flack, Switzerland), Interpretation of Results (L. Ricard, France), Data Deposition, CIF (J.C. Daran, France), Cambridge Structural Database (K. Lipscomb, F. Allen, UK), Multipolar Refinement and Charge Density Analysis (C. Lecomte, France).The atmosphere was excellent, with a lot of discussions between scholars and students around coffee, beer and glasses of French wine.

There were 70 participants coming not only from France, but also from Morocco, Algeria, Tunisia, Croatia and the Ivory Coast.

Jean-Claude Daran