X-Ray Diffraction Laboratory

 

X-ray crystal structure determination is an important technique for most inorganic and organic chemists. The X-ray Diffraction Laboratory at UM St. Louis supports the research programs of several research groups in the department. Also, we collaborate with a number of groups elsewhere in the USA and in other countries in their solid-state structure determination research. The Laboratory is equipped with state-of-the-art instrumentation and computational facilities for solid state three dimensional crystal and molecular structure determinations. The facility is located in custom-designed laboratory space in the Center for Nanoscience, opened in November 1996, and currently houses single crystal and powder diffractometers.

For more information please contact Dr. Nigam Rath at (314) 516-5333 or by email: rathn@umsl.edu

Single Crystal X-Ray Diffraction Instrumentation

The Bruker APEX II Kappa Dffractometer is equipped with an Oxford Cryostream low temperature device. Fast data collections can be carried out using this Kappa geometry diffractometer equipped with a 4K CCD (Charge Coupled Device) chip at 100-300K. This instrument uses a sealed tube Mo x-ray source. Currently, most of the structure determinations are carried out using this system.

The Bruker SMART APEX II Diffractometer: This CCD (Charged Coupled Device) area detector system was updated recently to a state of the art Apex II detector equipped with a 4K CCD chip and Oxford Cryostream low temperature device for use in smal molecule crystallography. Currently this instrument is primarily used for teaching and training of students and Post-doctoral researchers as well as for data collection by others.

Powder Diffraction Instrumentation

A Rigaku Ultima IV Powder Diffractometer is used primarily for bulk material characterization, including air- and moisture-sensitive samples. This provides a valuable analytical tool for the identification of single and multi-component solids by comparison with known published powder patterns. It is also used to determine the homogeneity of crystalline samples from which single crystals have been used for crystal structure determination. This instrument is also capable of data collection for small angle x-ray scattering (SAXS) experiments.

Computer Facilities and Other Instrumentation

The X-ray Laboratory Computing Facility has several workstations running crystallographic software. All computers in the lab are integrated with the university computer network. The Cambridge Structural Database is accessible to all university computer system users and is hosted through a Sun server and available on all computer lab PCs.

The sample preparation laboratory is equipped with stereo microscopes for screening and photographing crystals. These microscopes are also used for crystal mounting for x-ray data collection. A fume hood, a refrigerator and freezer for crystallization and sample storage, together with other necessary facilities for crystallization and crystal handling are available in the x-ray diffraction laboratory.