These slides walk students through a solid state synthesis with a simple powder XRD analysis. This presentation was made to answer the question “How do I know what came out of the furnace?” for a general chemistry audience, assuming very little XRD knowledge. Specifically this shows using XRD with database searching to determine phase purity through pattern matching.
(This does not cover the fundamentals of XRD, please see related links for that.)
Students will be able too:
- Learn the steps involved in checking phase-purity using powder XRD
- Learn that all peaks must be accounted for to fully characterize the XRD pattern
- Be able to use XRD as a simple technique for pattern matching without an extensive background about why it works.
This presentation has been utilized in general chemistry courses in which students were completing solid state syntheses. The slides were posted on course websites and also presented during lecture in large enrollment courses, in a short amount of time; < 10 minutes. The students were able to view XRD as a tool to determine phase purity of their samples. (Later students went into the lab to analyze their own syntheses with XRD.) In some instances these slides were coupled with other presentations/activities/lab assignments that were focused on how and why XRD works for polycrystalline samples. (These other items are not available to post here, though the links provided as “related activities” are comparable.)
Student understanding was noticed in conversations during data collection, with instructor or peer mentors, and at their final poster presentation with peers, instructors and department members.
Students had a general idea of why they were using XRD to analyze their samples. Most students were able to report the purity of their samples correctly. Several students did not consider the additive nature of impure samples; that is if two or more phases were present, then peaks from all phases would be present. Some students also did not consider the possibility of peak overlap with multiple phases.