This lab was part of the materials science portion of my second-year inorganic chemistry course. Students synthesize a zeolite structure and grow a chemical garden as examples of silicate chemistry.
I paired this lab with several prelab exercises that included visualizing the zeolite structure (see related activities), reading a current literature article related to an active research collaboration at the school, and writing a step-by-step procedure from the literature methods section to gain practice in planning out experiments (and to appreciate the differences between lab manul procedures and a formal methods section). For simplicity, these prelab components have been eliminated from the VIPEr version of the lab, but the experiment could easily be expanded to include prelab activities that match your own research and departmental interests.
We saved the students' zeolites and attempted to use them as catalysts for the aquation of hexammine cobalt (III) complexes in a later lab experiment, but the analysis was complicated by students using inconsistent quantities of material and by residual base from the zeolite synthesis, which affected the pH of the later reaction. Since zeolite surfaces are expected to be catalytic, this might be an interesting avenue to explore in a more advanced class or with stricter experimental controls.
Students will gain experience with silicate chemistry and will be introduced to the industrial applications of zeolites.
Powder x-ray diffraction will be used as an analytical tool for determining material structure.
See prep instructions for a full list of all chemicals and equipment required (quantities calculated for a 12-student lab, working individually).
See instructor notes document.
Lab notebooks were collected and graded for all students. In addition to a condensed introduction and thorough lab procedure/observations section, students discussed how well their x-ray data matched (or didn't match) the results of the instructor and other students in the lab. (Ideally, we would have compared to an inorganic structural database, but our campus does not subscribe to these sites, and I was unable to find a free one. If this resource were available, it would be interesting to have students assign peaks and calculate cage size based on diffraction angle.) Each student wrote a short conclusion and discussion of experimental error and answered the postlab questions.