Return to Contents Useful Concepts Useful Concepts

Oxidation and Reduction

Oxidation: Reduction: Calculating Oxidation Number or State (there are several methods for doing this, pick the one that works for you !)
This allows for a more formal, quantitative decription of the oxidation state for the C atoms and is based on looking at what atoms are attached to the C atom in question. The algebraic sum of the oxidation states must equal the charge of the molecule.
Here are a few examples, and a couple of schemes that show important relationships:

Calculating oxidation state
Oxidation state and Redox relationship of Hydrocarbons
Oxidation state and Redox relationship of oxygen functional groups

Tips:  In General Chemistry or High School you may have learnt that O is always -2, however it is better to count each bond to an O as -1 since there is a difference between C=O and C-O as seen by comparing the aldehyde and the alcohol in the diagram above. After all , the -2 statement is wrong.... for example in oxygen gas, the oxidation state is zero


organic chemistry © Dr. Ian Hunt, Department of Chemistry University of Calgary
>