27 Jun 2016

Determining transition metal oxidation states: Recognizing bond metal-ligand types

In-Class Activity

Submitted by Brandon Quillian, Armstrong State University
Categories
Description: 

In this in-class activity, students will determine the formal oxidation state of transition metal complexes by performing bonding type analysis of ligand−metal bonds. This in-class project is intended for those with little background in inorganic chemistry and aims to provide simple methods to calculate the formal charge of transition metals through bond-type analysis. While there are more sophisticated models already available to assign transition metal oxidation states, such as the LXZ (CBC) model, this exercise is intended for students who are coordination chemistry novices.

AttachmentSize
File BondingAndOxidationStates.docx371.08 KB
Learning Goals: 

On completion of this activity, a student will be able to:

  • calculate formal charges of ligands;
  • determine if the ligand metal interaction is Lewis derived or covalent;
  • assign formal oxidation states to metals with somewhat complicated ligand interactions
Implementation Notes: 

Students are paired in groups of two and given time to work on the problems. After completion, the instructor provides the solution to two of the problems then the students are given additional time to reflect on and correct their answers.

Time Required: 
30-45 min
Evaluation
Evaluation Methods: 

Students are given a follow-up problem set.

Evaluation Results: 

Preliminary results reveal that students have difficulty understanding the bonding interactions between the metal and the cyclopentadienyl ligand (principally recognizing its negative charge). Additional instruction on this concept may be required.

Creative Commons License: 
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