21 Apr 2009

Introduction to X-ray crystallography

Web Resources and Apps

Submitted by Adam R. Johnson, Harvey Mudd College
Categories
Description: 

At the end of my inorganic course, I teach several "cool" analytical techniques that inorganic chemists use.  These techniques are discussed within the context of bioinorganic chemistry, and I typically cover EXAFS/XANES, X-ray crystallography, EPR and Mössbauer.  I provide this website to the students as supplemental reading material for X-ray crystallography, which is not typically covered in depth in an introductory inorganic text.  The first link is the main website, but I usually only focus on the 2nd and 3rd links which covering the experimental setup for an X-ray diffraction experiment and the meaning of resolution.  If you click on the 2nd and 3rd links directly, you lose the framing;  so it might be better to click on the first link, and then select "Experimental Setup" or "Experimental Setup/About Resolution"

Learning Goals: 

After using these web resources, a student should have an appreciation for the general features of X-ray crystallography, including basic experimental setup and space groups, and understand what different resolutions mean in a metalloenzyme structure.

Implementation Notes: 

The "crystallography 101" site has lots of resources, lots of great pictures of crystals and diffractomoters and diffraction patterns.  I don't teach this topic in detail, I mostly just provide them with a framework to see crystallography in context of yet another characterization method, and that the major take home data are bond lengths and angles.

Time Required: 
various; I use one lecture period
Evaluation
Evaluation Methods: 

The only thing that I really expect my students to get out of the X-ray crystallography unit is an appreciation for limitations (resolution),  the iterative process between model and fit, and that your result is only as good as your data and your model.  I hope that the students gain an appreciation for the technique, and can understand a bit better what the X-ray data mean in the next research paper that they read.

Creative Commons License: 
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