Many extended structures can be viewed as close-packed layers of large anions, with the smaller cations fitting in between the anions. Larger holes between close-packed anions can hold cations with octahedral coordination. Smaller holes between close-packed anions can hold cations with tetrahedral coordination. The online jsmol resources show these layers and their holes.
The Committee on Professional Training (CPT) has restructured accreditation of Chemistry-related degrees, removing the old model of one year each of General, Analytical, Organic, and Physical Chemistry plus other relevant advanced classes as designed by the individual department. The new model (2008) requires one semester each in the five Foundation areas: Analytical, Inorganic, Organic, Biochemistry and Physical Chemistry, leaving General Chemistry as an option, with the development of advanced classes up to the individual departments.
The goal of this activity is to have students calculate the empirical formula of a compound given the contents of a unit cell.
A repeating building block, or unit cell, is used to represent extended structures since shifting a unit cell along its edges by the length of the edge will exactly replicate the extended structure.
The page has JSmol structures for unic cells including cubic, body centered cubic, and face centered cubic unit cells as well as for CsCl, Ni3Al, Cu2O, NaCl, CaF2, ZnS, diamond, Li3Bi, NaTl, NiAl and ReO3. The advanced page also has triclinic, monoclinic, hexagonal, orthorhombic, and tetragonal cells with all possible centering.
Although I’m a solid state chemist, I still find it difficult to teach the visualization of solid state structures. I’m interested in any tool that helps my students visualize solids. My experience is that the more representations students can master, the more likely they are to find one that helps them understand solid state structures.
I’ve used many tools. These include
We do not cover extended solids (solid state materials) in our general chemistry program. With the exception of students who have taken a course in materials science, Inorganic Chemistry I is the first time our students have encountered solid state structure. Although they have built some visualization skills by working with molecules and symmetry, they do not have robust 3D visualization abilities and have trouble using the language of solid state chemistry (unit cells, packing, filling holes, coordination number, etc…) in the context of structure.
This is a short worksheet that guides students through simple metal lattices (SCP, CCP, HCP) and how filling holes in these lattices results in ionic lattices (NaCl, CsCl, fluorite, etc.).
The worksheet was used as an in-class activity after students had read about the material in the text. This activity is probably suitable for first-year students, though I used it with juniors/seniors.
This list includes a number of LOs to help in teaching nanomaterials subjects; however, it is not exhaustive.
Updated June 2018.
The Cambridge Crystallographic Data Centre (CCDC) provides many free programs that can be used to view and manipulate crystal structures. Additionally, they have made a subset of the Cambridge Structural Database (CSD) available for teaching purposes and many educational activities have been created to go along with this teaching subset (see link below). This teaching subset can be freely viewed through the WebCSD interface or can be used in the freely-available Mercury program. (Mercury is avaliable for Mac, Windows, and Linux systems.)
Towards the end of the semester, when we were starting to read more of the primary literature, I realized that the Miller Indices were present in most of the papers that I wanted to discuss. However, I couldn't find any good resources in textbooks that would help to explain what these were. I found this online resource through the University of Cambridge that is engaging, interactive and concise.