Measures of Similarity and Pseudosymmetry

Dec 172006
 

J. Appl. Cryst. (2006), 39, 842-849.    [ doi:10.1107/S0021889806038489 ]

A sizeable proportion of structures with Z‘ = 2 are thought to exhibit pseudosymmetry, but establishing the extent of the deviation from true symmetry is problematic. By considering both the conformational similarity between the independent molecules and the way in which they are related in space, assessment of the pseudosymmetry of a structure becomes possible. A method of matching two groups of atoms where both these factors are quantified using CRYSTALS [Betteridge, Carruthers, Cooper, Prout & Watkin (2003). J. Appl. Cryst. 36, 1487] is described.

Dr. Francesco Punzo

Jan 012006
 

Francesco obtained his PhD in Rome and since 2004 is Assistant Professor at the Chemical Division of the Department of Pharmaceutical Science of the University of Catania, Italy. He spent some months during 2005 and 2006 in our lab to improve his knowledge of crystallography. His principal area of research is the comparison of experimental X-ray diffraction data with computationally simulated data. The prediction of crystal morphology, polymorphism, atomic displacement parameters (adp), as well as the physico-chemical properties of biologically active compounds are among his interests.