| McMaster Analytical X-Ray Diffraction Facility (MAX) |
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Dr James F. Britten, Manager Dr Hilary Jenkins, Research Scientist, SCD Specialist 2012 Canadian Chemical Crystallography Workshop X-ray Diffraction for Nanomaterials (MATLS 4GO3) 3D Diffraction for Materials Characterization (from FXMA seminar at Albany Nanotech)
Phase transitions in Yeupeng Zhang's (MSE student) thin films, viewed in MAX3D .
Can you see the difference? Center spot from cubic, the rest from tetragonal split. Note the diffuse streaks in between. X-ray Crystallography is used to determine the structures of molecules and extended solid state lattices through the analysis of diffraction patterns from single crystals. It gives elemental analysis, bond lengths, bond angles, stereochemistry, intermolecular contacts, and even absolute configuration . . . in just a few hours! This molecule was synthesized by Michael Beer in the Chemistry Department's Valliant group.
X-ray Powder Diffraction is used to characterize polycrystalline powders and solids. Diffraction patterns are collected for sample identification, phase and polymorph analyses, texture and residual stress analyses, structure refinement, and ab initio structure solution. The X-ray service laboratory has been set up jointly by the Department of Chemistry and McMaster's Brockhouse Institute for Materials Research (B.I.M.R.). to provide efficient, professional, single-crystal and powder X-ray analyses at a reasonable cost to users. Facilities The laboratory has two single crystal diffractometers for X-ray analyses on many sample morphologies.
The Bruker Mo Smart APEX2 is used for inorganic and organometallic crystal structure determination as well as steel XRD2.
The Rigaku Cu rotating anode generator has parallel focusing mirrors, a three circle Bruker D8 diffractometer and a SMART6000 CCD detector. The Cu diffractometer is used for organic small molecule single crystal structure determination as well as 2D powder diffraction, fiber diffraction, texture or strain analyses on thin films or metal alloys.
Also located in the facility is a high resolution Bruker D8 Advance Powder diffractometer with a Ge monochromator. This instrument is capable of performing high resolution ab initio structure studies on solid state and molecular compounds. A Nicolet automated diffractometer is also available for use.
All of the single crystal diffractometers are equipped with low temperature attachments. The facility also offers a microscope and sample preparation room as well as an open office area for structure solution. The SHELXTL software package is distributed on PCs throughout the Department. The staff is involved in internal and external collaborations and welcome inquiries from interested parties.
Operating Policies Policies and procedures for the operation of the laboratory are determined by discussion and agreement between the manager and the Chair of the Department of Chemistry. Major changes are brought before the Facilities Committee for approval. The Chair has the final word. The facility is financed by users fees to recover the costs of maintenance and supplies. Processing of Samples Samples are accepted on a "first-come, first-served" basis and are assigned to the appropriate diffractometer. The names of the researchers (usually graduate students) are placed in a queue for each instrument. The users are encouraged to select and mount their own samples (0.02 - 0.50 mm crystals), and frequent users are trained to use the diffractometers. All operations are monitored by the manager.
Graduate Courses A graduate course in small-molecule crystallography is offered every year. It comprises lectures, as well as laboratory work (solving a structure), and tutorial sessions.
Cambridge Structural Database System Documentation (McMaster access only) PC-PDF Notes (McMaster access only)
International Union of Crystallography
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