X-Ray Diffraction

X-ray diffraction (XRD) uses the interaction of X-rays with crystalline materials to identify mineralogical composition and obtain detailed information about the crystallographic and physical properties of materials. The most common application is identifying compounds, including minerals, in a powdered specimen. Quantitative analysis is possible through fitting the measured pattern with patterns calculated from known crystal structures. Further information, including cell parameters, which typically correlate with chemical composition, and anisotropic crystallite dimensions may also be obtained.

EMSL’s microbeam diffractometer allows examination of small specimens, mapping of mineralogy across a surface, and protection of air-sensitive specimens in a fine glass capillary. Other specialized instruments include high and low temperature stages, as well as high-resolution optics for studying epitaxial thin films. EMSL maintains software for data analysis, and the latest diffraction database from the International Center for Diffraction Data.

Research application

XRD supports the Terrestrial-Atmospheric Processes Integrated Research Platform and the Biogeochemical Transformations Integrated Research Platform by characterizing the minerals or other crystalline compounds in environmental samples. The mineralogical composition can have a profound effect on how nutrients, contaminants, aerosols, and organic matter interact within and between ecosystems. In leveraging these observations, we are able to better predict the behavior of chemical compounds in the environment, as well as ecosystem responses to environmental perturbations.

Available resources

• Powder XRD
• Microbeam XRD
• Epitaxial Thin Film XRD

Tips for success

• The best results are obtained from fine-ground powders about the consistency of flour. One hundred mg or more is typical for the powder XRD, although specimens as small as 10 microns can be handled with the microbeam instrument.