When transitioning into inorganic chemistry from organic chemistry, students are surprised by the complexity of metal complexes. To ease this transition, students are asked to look at the crystal structure of a coordination complex [(+/-)cis-dichloro-bis(ethylenediamine)-cobalt(III) chloride monohydrate], make some observations about what they see, and provide a list of questions that they would like answered. Students usually note that there are atoms/ions that are "floating" and are seemingly unattached to anything else in the structure. They also make observations about the cobalt and the groups that are attached to it. After the students complete this activity, the instructor leads a discussion and tries to answer some of the questions and provide some insight into the structure.
This activity is used as a first-day activity to introduce them to coordination complexes and to get students accustomed to using their iPads in a new workflow. It can be completed on paper or on a laptop computer (different versions of the activity are provided) either in-class or as a homework assignment. This activity can also be used later in the semester just before coordination complexes are discussed.
After completing this assignment and participating in the subsequent discussion, students should be able to:
- view a crystal structure on the CCDC's Access Structures website,
- look at a crystal structure and make observations about the structure,
- identify the groups that are directly attached to the metal center and those that are not attached, and
- make analogies to what they learned in previous classes.
This activity can be completed with just a pen and paper if desired. A student could also use a laptop computer or an iPad to view and manipulate the structure, take a screenshot, and enter their responses into the document.
I have supplied several different versions of this document on the VIPEr site so that it can be used in many different ways.
- ALF_VIPEr_FirstLookCoordinationComplexes : This version is flexible and can be used by a student who will complete the assignment using a laptop.
- ALF_VIPEr_FirstLookCoordinationComplexes_iPad : This version of the file has instructions for how to take a screenshot on an iPad.
- ALF_VIPEr_FirstLookCoordinationComplexes_Screenshot : This version of the document can be printed off and distributed to a class. The screenshot of the coordination complex is included in this document.
In my course, I distribute this assignment as a PDF file through my course management system. During the first class meeting, I ask students to download this activity and complete it. Since all of my students have iPads and Apple Pencils, I want them to be able to complete this with that technology and to see how they can use the Apple Pencil to add annotations to the document. I leave about 20 minutes at the end of the class meeting to collect student observations/questions and to lead a discussion about this activity.
This activity is not graded or assessed in any way in terms of content. It is, in essence, a way to prompt students to make observations and ask questions about the structure of a coordination complex. I do observe my class to see if they can follow the workflow and access the structure, take a screenshot, insert it into the document, and submit it to the course management system.
Students are able to follow the workflow very easily and all of my students are able to complete this activity with little to no help from me. I am always pleased with the observations that they make and their willingness to participate in the discussion when they have questions. Typical student responses are included in the Instructor's Note document that is included with this learning object.
As usual, a great LO. I'm going to approve it but I have a few things I noticed or questions that maybe you could address in a comment or in the instructor notes section.
- maybe a discussion of why there are no H's? (I'm guessing its because the structures are from 1965 and 1968)
- why 2 isomers and 2 unit cells (is one a low T structure?)
- is there a more recent structure of this in the CSD that you could provide a code for to compare with a modern structural determination?
I like the open-endedness of this LO. I can totally see using this in my class... definitely a good first day activity. I also like that you come back to it when you discuss more advanced coordination chemistry later on.