Crystallography

The Virginia Tech Crystallography Lab (VTX) was formed by combining the resources of the Departments of Chemistry, Geosciences and Biology with support from the College of Science. VTX operates five diffractometers and is able to collect data on a broad range of single-crystal samples (e.g. small molecules, frameworks, minerals and proteins). The Department of Chemistry operates two diffractometers as part of a service center: the Rigaku Oxford Diffraction “Synergy” (NSF MRI Grant 1726077) and the Rigaku Oxford Diffraction “Gemini”.

  Huber Xcal1 Xcal2a Gemini Synergyb
Purchase Year 2001 2001 2002 2006 2018
Service       Yes Yes
Teaching       Yes Yes
Research Collaboration Yes Yes Yes   Yes
Precise unit cell parameters Yes        
Minerals   Yes Yes Yes Yes
Small molecules/MOF       Yes Yes
Absolute Stereochemistry       Yes Yes
Biological macromolecules         Yes
High pressure mineral structure   Yes Yes   Yes
High pressure framework structure   Yes     Yes
Very small samples         Yes
Multiphase crystals   Yes   Yes Yes
100–300K       Yes Yes
300–500K Yes       Yes
500K–800K Yes        

aPurchase of XCal2 was supported by the National Science Foundation
bPurchase of Synergy was supported by the National Science Foundation under Grant No. 1726077

Services offered on Synergy and Gemini

  • Crystal screening and mounting, including air-sensitive samples
  • Structure solution, refinement, and interpretation of chemical/mineral/materials samples
  • Cambridge Crystallographic Database searching
  • Specialized Experiments (see below)
  • For more details about the service center, go to the service center website.

Specialized Experiments (including powder XRD, fibers, thin films, etc.)  

The diffractometers are designed for single-crystal samples.  Other techniques (including powder diffraction) are considered ‘specialized’ and are only offered by special request and with adequate justification for the need of the single crystal instruments as opposed to instruments specifically designed for such experiments.

Macromolecular single-crystal XRD

This must be done in collaboration with a protein crystallographer: VTX staff will gladly assist with data collection but we are not trained in protein crystallography.  Users must be prepared to assist the crystallographer in the lab; structure solution and refinement services are NOT available.

High Pressure Crystallography

VTX has the unusual capability to collect in-situ high-pressure single crystal data (up to 10 GPa). These experiments are highly specialized and are offered through research collaboration with Professor Nancy Ross.

Courses and Training

CHEM 5984 (Fall 2018, 1 credit P/F): The goal of the course is to provide students with a hands-on introduction to crystallography.   The target audience is students who use crystallography as a tool in their research and who submit samples to the X-ray Service Center for analysis (but do not use crystallography enough to take the 2-semester course qualifying them to work independently).

CHEM 5525/GEOS 5535 (Fall 2018, 3 credits): Covers the means of describing a crystalline solid, including lattices and symmetry (i.e. 2D and 3D point groups, 2D plane groups, and 3D space groups), allowing for the formal description of structures and surfaces and the interpretation of published crystallographic data.  This course is a prerequisite for CHEM 5526/GEOS 5536. Undergraduates who have taken CHEM 3615, GEOS 3504, or an equivalently rigorous course are welcome to register.

CHEM 5526/GEOS 5536 (Spring 2018, 3 credits):  Covers diffraction theory and practical aspects of single-crystal and powder X-ray diffraction. 
CHEM 5525/GEOS 5535 is a prerequisite.  Students who complete this course are permitted to work independently in VTX.

Cambridge Crystallographic Database

Virginia Tech has a site license to the Cambridge Structural Database. For occasional users of the database, the WebCSD can be accessed from any computer with a Virginia Tech IP address. Users who need frequent and/or specialized searches, or who need access to a CSD software suite (CSD-System, CSD-Materials, or CSD-Discovery) should contact Dr. Slebodnick for download instructions.