The colors of transition metal compounds are highly variable. Aqueous solutions of nickel are green, of copper are blue, and of vanadium can range from yellow to blue to green to violet. What is the origin of these colors? A simple geometrical model known as crystal field theory can be used to differentiate the 5 d orbitals in energy. When an electron in a low-lying orbital interacts with visible light, the electron can be promoted to a higher-lying orbital with the absorption of a photon. Our brains perceive this as color.
This is a truly hands-on activity in which students manipulate paper cutouts of carbon atomic orbitals and oxygen group orbitals to identify combinations with identical symmetry and build the carbon dioxide molecular orbital diagram. The activity pairs well with the treatment of MO theory in Miessler, Fischer, and Tarr, Chapter 5. An optional computational modeling component can be added at the end.
<p>This is an in-class activity I made for my students in a Junior/Senior-level one-quarter inorganic course. </p><p>Unfortunately it was waaay too long for the 1.5 h class (i gave them about 45 min). I recommend taking this and adapting it to a take-home exercise or homework set, which is probably what I will do this coming year. </p><p>Students used Otterbein to look at various structures, starting with low symmetry, working up to very high symmetry structures.
Orbital Viewer (http://www.orbitals.com/orb/ov.htm) is a PC-based program that shows electron density calculated from the Schrodinger equation for atoms and molecules. Results can be shown as probability densities or probability surfaces.
Orbital Viewer Program copyright 1986-2004 by David Manthey
The Materials Project is part of the Materials Genome Initiative that uses high-througput computing to uncover the properties of inorganic materials.
It's possible to search for materials and their properties
It employs high-throughput computation approaches and IT to create a system that can be used to predict properties and construct phase diagrams andPourbaix diagrams.
Hilary first higlighted this resource as a news item before we had a web resource category. I'd like to bring it back to people's attention as a web resource because of its value.
Students use a Java-based website to explore the faujasite zeolite structure. The activity questions guide them through identifying different atomic positions within the structure, and orienting the zeolite pores and "cages" relative to the crystal axes.
In this activity, students will compare and contrast two closely related structures, [Pd(dcpf)PR3]2+ (dcpf = 1,1'-bis(dicyclohexylphosphino)ferrocene; R = Me or Ph). They will be required to obtain the cif files from the supporting information of a paper. They will then make a variety of measurments in the two stuctures. These measurements can be made using a variety of different freely available programs. Instructions are provided for Mercury 3.3 and Olex2. Finally, students will be required to provide a rationale for the differences in the two structures.
This suite of activities can be used as a unit exploring the use of small molecule models and biophysical techniques to illuminate complicated biomolecules. The Parent LO: Modeling the FeB center in bacterial Nitric Oxide reductase is a short, data-filled and well-written article that is approachable with an undergraduate's level of understanding.