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X-ray Diffraction

Louvain-La-Neuve

Our group coordinates and performs the X-ray diffraction activities of the platform.

Structure determination of single crystals

X-ray single crystal analysis returns the 3D composition of the molecules or complexes of interest.
The atomic nature and spatial arrangment are precisely determined and the relative orientation and the inter- or intramolecular interactions, such as hydrogen bonds or ionic interactions, can be studied in detail.

Structural determination of chemical compounds (organic, inorganic molecules, macromolecular complexes, ...)

The structural information can serve to:

  • Identify the compound (unit cell determination may do the trick)
  • Verify the configuration and determine the geometry (interatomic distances and angles)
  • Determine the solid state conformation of the molecule
  • Obtain 3D coordinates (as a starting point to start calculations)
  • Analyse the intra- and intermolecular interactions
  • Identify and analyse polymorphes (also possible in function of temperature)
  • Determine the absolute configuration (when certain conditions are met)

Profile of a good crystal

  • Size: 0.1-0.5 mm (~ visible with the naked eye)
  • Morphology: not so important, often single crystals are characterized by well defined edges
  • Often it is necessary to keep the crystals in solution as some crystals degrade outside the mother liquid. In doubt of the crystal stability, keep them in the crystallizing solvent.

Equipment

Our current X-ray diffraction infrastructure consists of two Incoatec generators (Mo radiation) equipped with MAR345 image plate detectors. 

  • A microfocus beam setup consisting of a Incoatec source and a MAR345 image plate detector is used to measure single crystals.
  • A high-brilliance Incoatec source with a larger beam is combined with a MAR345 image plate detector to measure powder samples in capillaries (transmission mode)
  • An oxford Cryosystem is available for low temperature measurements as well as a heat blower for high temperature conditions.

INCOATEC IµS Microfocus source with a Mo ELM33 optics with focus on the sample position

  • Mo (0.71073Å)

INCOATEC IµSHIGH BRILLIANCE source with a Mo ELM47 optics with focus at the dectector

  • Mo (0.71073Å)

3 MAR345 image plate detectors

Oxford Cryostream

  • Accurate temperature
  • 80 - 400 K range
  • Programmable (allows temperature dependent measurements)

Procedure to follow

  • Download the following document and send it back to Dr. Koen Robeyns: Analyse_Xray
  • The responsible agrees to the analysis by signing a printed version of this document, which should accompany the sample.
  • The structural analysis requires a single crystal and results in accurate atomic positions of the studied compound. (organic, inorganic molecules, macromolecular complexes, ...)

This service is open to the members of the Institute of Condensed Matter and Nanosciences (IMCN) and the UCLouvain, but equally to external academic or industrial users.