Description of the X-ray diffractometer (Bruker KAPPA APEX II)

Apparatus

Bruker KAPPA APEX II is the top of the line solution for a sealed tube crystallography from Bruker. The X-ray diffractometer combines the high versatility of the 4-circle kappa goniometer with the very sensitive and fast CCD detector APEX II, and is therefore one of the best instruments for structure determination. The instrument is equiped with the 700 series Oxford Cryostream unit, which allow fast cooling to 100 K in just 20 minutes by a cold stream of nitrogen gas. The 60 L dewar can supply cold nitrogen gas for 4-5 days with out refilling and has further the advantage that it can be refilled with liquid nitrogen without affecting the crystal temperature.

The Bruker KAPPA APEX II diffractometer

Use
The X-ray diffractometer is used for determining the crystal structure of both organic and inorganic compounds. By recording the diffracted beam from X-rays hitting a single crystal, the unit cell can be determined from the positions of the diffraction spots. The exact atomic position within the unit cell can then be determined from the intensity of the spots.

The 700 series Oxford Cryostream system containing a 60 L dewar, a silent Dry Air Unit, a controller unit and a diaphragm pump unit.

Close up picture of the APEX II detector (right), KAPPA goniometer (middle below), cryostream unit (middle on top), The X-ray tube (left) and a camera for positioning the crystal in the beam (left on top).

Publications:
A pyroelectric material Authors: Michael Pittelkow, Theis K. Reenberg, Kim T. Nielsen, Magnus J.Magnussen, Theis I. Sølling, Frederik C. Krebs and Jørn B. Christensen*. Journal: Angew. Chem. Int. Ed., 2006, 45, 5666-5670