Institute of Crystallography - CNR

Single Crystal X-Ray Diffractometry Laboratory

The Bruker-Nonius KappaCCD single-crystal X-ray diffractometer provides diffraction data that allow to carry out the structural characterization of crystalline materials with different chemical composition and complexity (small and medium molecules, up to about 150 non-H atoms in the asymmetric unit): synthetic compounds (organic, inorganic and metalorganic compounds, including, for example, new materials of technological and pharmaceutical interest) and natural compounds (e.g., minerals), with the possibility of investigating also materials that diffract weakly (via low-temperature diffraction experiments, using a nitrogen cryostat) and unstable in air and/or thermolabile samples (thanks to the X-Temp 2 device).

Therefore, the Bruker-Nonius KappaCCD X-ray diffractometer allows to carry out research and technology transfer activities aimed at revealing the structure-property relationships of crystalline materials, at determining the crystal structure of reaction products, at studying the reaction mechanisms and the stereochemistry of products, at identifying the main intermolecular interactions, at validating synthetic compounds, at determining the absolute configuration of chiral molecules.

In order to carry out the diffraction experiment, a crystal of suitable size (i.e., fractions of mm) is selected with the help of an optical microscope; the chosen crystal is mounted on a glass fiber introduced in a goniometer head and is aligned by the fine movements of the goniometer head and with the help of a videomicroscope.

The diffraction experiment consists of a first preliminary quick data collection, which requires the acquisition of a few diffraction images and is aimed at determining the cell parameters (i.e., the first step of the ab-initio structure solution process) and the orientation matrix, followed by a second data collection, that is longer and richer in images in order to allow the attainment of the diffraction data completeness necessary for the success of the structure solution and refinement process.

At the end of the diffraction experiment, the data reduction software available for the Bruker-Nonius KappaCCD diffractometer allows to extract and correct for absorption effects the integrated intensities that will be used in the next steps of the ab-initio structure solution process (i.e., space group determination, structure solution and refinement).

Bruker-Nonius KappaCCD X-ray Diffractometer

The Bruker-Nonius KappaCCD single-crystal X-ray diffractometer consists of a) an X-ray generator (FR590, max power 3.0 kW); b) a sealed X-ray tube (molybdenum anode, ‘Fine Focus’ type; c) a Kappa geometry goniometer; d) an area detector (CCD), e) a videomicroscope. The diffractometer is equipped with a device for low-temperature measurements (nitrogen cryostat, 700 Series Cryostream Gas Cooler, operating in the 80-400K temperature range) and a device for handling air-unstable and/or thermolabile compounds (X-Temp 2). The radiation is monochromatised (MoKα = 0.71073 Å) by a graphite monochromator and a nickel filter. The size of the incident beam is varied by means of a collimator (diameter size: 0.25, 0.35 or 0.6 mm). The Kappa geometry goniometer allows to flexibly orient the sample and, thanks to its smaller dimensions compared to those ones of a four-circle goniometer, enables to sample zones of the reciprocal lattice that are not accessible by a four-circle goniometer. The area detector allows to carry out the diffraction experiment within a few hours.

Scientific manager
Technical manager
Tel: +39 080 5929156 Fax: +39 080 5929170