Crystal Field Theory and Gems--Guided Inquiry

Submitted by Adam Johnson / Harvey Mudd College on Sat, 05/14/2016 - 21:42
Description

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.

Ligand Field Correlations for Square Pyramidal Oxovanadium(III)

Submitted by Matt Whited / Carleton College on Fri, 04/22/2016 - 10:37
Description

Students work in groups to derive the ligand-field diagram for a square-pyramidal vanadium(III) oxo complex using octahedral V(III) as a starting point. The activity helps students to correlate changes in orbital energies as a function of changing ligands and geometry as well as rationalizing why certain geometries can be particularly good (or bad) for particular complexes. The activity also helps students see why oxo complexes of early metals are frequently best described as triple bonds.

Otterbein Symmetry In-Class Activity/Take home activity

Submitted by Kyle Grice / DePaul University on Mon, 01/25/2016 - 21:26
Description

This is an in-class activity I made for my students in a Junior/Senior-level one-quarter inorganic course. 

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. 

Students used Otterbein to look at various structures, starting with low symmetry, working up to very high symmetry structures. I had them go through the "challenge" so they couldn't see the keys at first, but then go back to check their answers. 

Point Group Battles Activity

Submitted by Darren Achey / Kutztown University on Thu, 10/15/2015 - 11:48
Description

In this activity, a pair of students are show an object or molecule and are asked to determine the point group before their competitor.

Iron Cross-Coupling Catalysis

Submitted by Laurel Goj Habgood / Rollins College on Wed, 09/16/2015 - 13:08
Description

In this experiment, students will synthesize and characterize an iron complex followed by completion of two series of catalytic cross-coupling reactions mimicking the methodology utilized by organometallic chemists to balance catalyst efficacy and substrate scope.  Initially the complex Fe(acac)3 [acac =  acetylacetone] is prepared.  Two sets of catalytic reactions are completed: one comparing different iron catalysts (Fe(acac)3, FeCl2, FeCl3) while the other compares substrates (4-chlorotoluene, 4-chlorobenzonitrile, 4-chlorotrifluorotoluene).

Antibacterial Reactivity of Ag(I) Cyanoximate Complexes

Submitted by Kari Young / Centre College on Sat, 08/22/2015 - 14:09
Description

In this experiment, students will synthesize and characterize one of three Ag(I) cyanoximate complexes as potential antimicrobial agents for use in dental implants. This experiment combines simple ligand synthesis, metalation and characterization, and a biomedical application. The complexes are both air and light stable.

A Demonstration to Segue Between d to d and CT Transitions

Submitted by Marion Cass / Carleton College on Mon, 08/10/2015 - 19:21
Description

The following is a simple in-class “demonstration” that I use to segue between d to d and charge transfer transitions.  After teaching about d to d transitions and Tanabe-Sugano Diagrams, I show my students three solutions that I have put in large test tubes before class. The three solutions I place in the test tubes are:

a.  10 ml of 0.1M Co(H2O)62+

b.  10 ml of 0.1M Cu(H2O)62+

c.  10 ml of a freshly prepared 0.1 M KMnO4 solution

Peer Review - How does it work?: A literature discussion with a focus on scientific communication

Submitted by Mike Norris / University of Richmond on Thu, 07/02/2015 - 20:21
Description

This learning object is based on discussion of the literature, but it follows a paper through the peer review process.  Students first read the original submitted draft of a paper to ChemComm that looks at photochemical reduction of methyl viologen using CdSe quantum dots.  There are several important themes relating to solar energy storage and the techniques discussed, UV/vis, SEM, TEM, electrochemistry, and catalysis, can be used for students in inorganic chemistry.

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