Submitted by T Brown / SUNY Oswego on Sat, 06/03/2017 - 10:46
My Notes

This paper describes the synthesis and characterization of a Cr(I) dimer with a very short Cr-Cr distance. Computational studies support fivefold bonding between the chromium atoms. This paper could be used to introduce metal-metal multiple bonds and discuss the molecular orbital interactions of homonuclear diatomics including d-orbitals. More generally, it is a nice example to stimulate the discussion of what constitutes a bond and the various interpretations of bond order. This version of this learning object is a modified and expanded version of Maggie Geselbracht's original LO. It was prepared colleaboratively at the 2017 VIPEr Literature Discussion workshop.

Attachment Size
Questions for students 50.5 KB
Learning Goals
Students should be able to:
  • Identify shapes and orientation of d orbitals

  • Create Lewis structures describing ligand binding type from crystal structures.

  • Apply symmetry concepts to assign orbital symmetries and create molecular orbital diagrams

  • Develop and draw the MO diagram of d-orbital interactions and use it to interpret the bonding involved in metal-metal multiple bonds.

  • Evaluate the relationship between bond order and experimental metal-metal bond distance

  • Evaluate effects of ligand design on molecular stability

  • Apply character tables for associated molecular point groups      

  • Rationalize MO interactions of ligands with metal centers in the presence of a metal-metal multiple bond.


Implementation Notes

Students are asked to read the paper and answer the discussion questions before coming to class. This could be used in an inorganic course after you have talked about MO theory of diatomics but fairly early in our discussion of transition metal chemistry. There is a Perspectives article in Science that goes along with this paper that gives the MOs more explicitly.   

Time Required
50 min +
Evaluation Methods

Students are asked to answer the questions before coming to class and collected. After discussion students can revise their answers.   

Evaluation Results

This is a newly revised learning object so no assessment has been collected yet.  

Creative Commons License
Attribution, Non-Commercial, Share Alike CC BY-NC-SA


Gary L. Guillet / Georgia Southern University Armstrong Campus

I used this assignment as a literature discussion with my Inorganic Class (No P Chem pre-req).  I used it to close out the MO chapter (5 in Meissler and Tarr).  I really wanted to give the students a chance to apply what they worked to learn on a seemingly very complicated system that they had no experience with.  Try to build their confidence that MO was a tool to apply to things as opposed to a batch of content to learn.  I also wanted to replace lecture on delta bonding with a more active assignment.

 I wrote a Pre-Class quiz and gave it through our LMS to make sure they read the paper.  Then I used the questions posted above, with a few modifications, as a group exercise that I facilitated during a 75 minute lecture.  I wrote a rubric to grade the quiz, their participation, and their responses.

I think it worked well to get the students to focus in on a relevant example.  I don’t have any hard data to show it was more effective than what I did previously but I think it was easily more active than the lecture on this content i did previously.  It did take too much time though, my goal was to complete it in one 75 minute class, so I assigned the remainder for homework.

Thu, 06/25/2020 - 16:03 Permalink
John Lee / University of Tennessee Chattanooga