Experimental techniques of structure determination by X-ray diffraction



Experimental techniques of structure determination by X-ray diffraction


S. Maggi
B. Aresta
G. Chita
R. Lassandro


X-ray diffraction, crystal structure solution, experimental methods

Dept. of Chemistry, Università di Bari, Italy (http://www.chimica.uniba.it)
Dept. of Pharmaceutical Sciences, Università della Calabria, Italy (http://chimica.unical.it)
Dept . of Organic and Industrial Chemistry, Università di Parma, Italy (http://www.unipr.it/arpa/chimorg)
Dept. of Chemistry, Università di Urbino, Italy (http://www.uniurb.it)
Molecular Crystal Engineering, Dept. Of Chemistry, Università di Bologna, Italy (http://www.ciam.unibo.it/crystal_eng/index.html)
Laboratoire de Physico-Chimie des Matériaux, Faculté des Sciences, Monastir, Tunisia
Laboratoire d'Application de la Chimie, Faculté des Sciences, Bizerte, Tunisia


A first step in the study of the chemical and physical properties of new molecules is the accurate determination of their crystalline structure and the study of the dependence of the structure on the parameters of the synthesis.
The main research interest of the group is the experimental determination of the crystalline structure of single crystals (with sizes of the order of 0.1-0.3 mm and higher) and polycrystalline powders (sizes of the order of 1 micrometer) by X-ray diffraction, which is the main and more accurate technique to solve a crystalline structure from diffraction data.
Recently, we have focused our attention on zeolites, catalyzers and pharmaceuticals. However, requests of new collaborations from academic and industrial institutions to study innovative chemical compounds are welcome.
Data collection is carried out using a Nonius KappaCCD single crystal diffractometer working at room and liquid nitrogen temperature and a Rigaku powder diffractometer with an INEL linear detector. A new Rigaku powder diffractometer will be available soon.
The solution and refinement of the crystal structure is carried out using the packages developed in the Institute together with several competing software applications. This is necessary not only to check the quality of the solution but also to exploit the capabilities of the competing applications and to find new areas of development for our own packages.
Being a research institution we have never provided routine characterization of compounds as a service for external users. Nevertheless, we are open to requests from non-academic institutions and we will provide a detailed price list for each stage of the structure determination process.
In parallel with these activities, we develop and maintain the web site http://wwwba.ic.cnr.it, for the distribution of the software packages developed at IC and for the technical support of the registered users.
The web site has been developed last year using a modern CMS system and is online since Dec. 2009. We currently have nearly 3000 registered users who access the site mainly to download our packages and to read and contribute to the support forums.


Experimental techniques of structure determination by X-ray diffraction - Img

Figure 1. Crystal structure of a porphyrin-like cadmium complex [K(222)]•[Cd II (TPP)(SCN)] (unpublished).


Experimental techniques of structure determination by X-ray diffraction - Img

Figure 2. Asymmetric unit of NbCl5•(N,N'-dicyclohexylurea), determined by single-crystal X-ray diffraction (Aresta et al., Dalton Transactions, in press).





Sabino Maggi
Email : sabino.maggiATic.cnr.it
Tel : +39/080 592 9158/9152


Last Updated (Tuesday, 21 December 2010 16:59)