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This article describes the synthesis and characterization of ternary rare-earth gallium bismuthide, LaGaBi2. Band structure calculations are used in understanding the bonding in this material, analyzing the interactions of smaller substructures. This is a good example of what information can be learned from the band structures of an extended solid and exposes students to an interesting combination of elements in the periodic table that are often overlooked.
This LO was updated to include an answer key and the instructions for crystal structure visualization at the 2021 Summer Workshop.
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| Updated Discussion Question.docx | 20.23 KB |
Through this activity, students will be able to:
1) Discuss basic solid-state chemistry concepts including synthesis, characterization techniques, and computational chemical bonding and electronic structure analysis.
2) Develop an appreciation for the concerted efforts of experiment and computation;
3) Cross-reference literature to better understand techniques described in literature;
4) Apply prior knowledge to interpret data derived from tables and figures;
5) Interpret the calculated electronic structures and connect them to the crystal structure and chemical bonding features;
6) Inspect the tabulated X-ray crystallographic data and calculate the empirical formula from the unit cell contents.
7) Evaluate the role of the La3+ cation in the structure and in the electronic structure, based on its oxidation state.
8) Employ fundamental concepts of XPS and binding energies to learn the interatomic interactions.
9) Explain and interpret electronic transport properties measurements.
The text by Roald Hoffmann, "Solids and Surfaces: A Chemist's View of Bonding in Extended Structures" presents a good introduction on the essentials of solid-state chemistry.
Band theory builds nicely upon any advanced discussion of molecular orbital theory.
The students will be asked to read the article before class and submit their answers to the questions. In class, the students will be able to discuss their answers in small groups, and they will have to present the report of their discussion afterwards, maybe highlighting the main generalizations they gathered from the discussion.
Evaluation
1) Individual answers to the questions.
2) Group presentation of the discussion.
3) Individual evaluation of each member.
LO developed at the 2021 IONiC VIPEr workshop and will be updated when implemented.
In the previous LO, one of the feedback is about the students having trouble with assigning oxidation states.