This communication from the Journal of the American Chemical Society (J. Am. Chem. Soc. 2009, 131, 17084-17086. doi:10.1021/ja9080666) describes the use of classic solid state chemistry to dope Mn3+ in two different host oxide structures to create new blue pigments. The key to the blue color is the unusual trigonal bipyramidal coordination of the Mn3+ ion in these structures. Discussion of this paper in class provides an opportunity to discuss solid solution chemistry in extended structures, including both their synthesis and characterization as well as illustrate the application of crystal field theory to understand the color of a transition metal doped oxide. An extensive list of discussion questions is provided so that the learning activity can be tailored to a variety of different curricular uses and student backgrounds.
After reading and discussing this paper, a student will be able to:
- Describe the basic considerations in the design, synthesis, and characterization of solid solutions in extended structures.
- Identify and describe the distinguishing features of several different mixed metal oxide structures.
- Given structural information, apply the principles of crystal field theory to explain the color and electronic spectroscopy of a transition metal ion doped oxide.
An extensive list of potential discussion questions was developed by Barbara Reisner and Maggie Geselbracht, two faculty trained as solid state chemists so that other faculty would have a range to choose from and use, depending on their curricular goals. We believe that this is an ideal paper to introduce extended solids into the inorganic curriculum with the “hook” for both faculty and students of an easy connection to coordination chemistry.
The first time this learning object was used in the classroom was by Barb at James Madison University in Fall 2009 in a second semester Inorganic Chemistry Course. This paper was not originally used as a literature discussion but instead turned into a lecture. The lecture was used to tie up a unit on solid state chemistry, and the figures in the paper to discuss solid state structures and ionic radii; basic crystallography, powder diffraction, and Vegard’s Law; and crystal field theory.
Maggie used this literature discussion activity as the final conference for her sophomore-level inorganic chemistry course at Reed College in Spring 2011. She selected 8 of the discussion questions from the full list and provided them to her students in advance of the conference meeting. This shortened list is available as an attachment above. Students were asked to read the paper and write out the answers to the discussion questions prior to the discussion. The solutions document to these 8 questions is available to registered faculty users on VIPEr.