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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: FictionDurden on October 19, 2004, 12:39:53 AM

Title: Absolute and Relative Configurations
Post by: FictionDurden on October 19, 2004, 12:39:53 AM

For an upcoming exam, I will have to compare and contrast absolute and relative configurations. The problem is, I need  3 compares and 3 contrasts for these configurations. I am not totally sure of what absolute and relative configurations are. I can only think of 1 contrast, and that is their definitions. *delete me*

Title: Re:Absolute and Relative Configurations
Post by: movies on October 19, 2004, 04:38:14 PM

Think about the other implications of the definitions.

Why don't you start by telling us the definitions and we can help you from there.

Title: Re:Absolute and Relative Configurations
Post by: FictionDurden on October 19, 2004, 05:20:11 PM

Absolute configuration - the detailed stereochemical picture of a molecule, including how the atoms are arranged in space. Alternatively, the (R) and (S) configuration at each chirality center.

Relative configuration - the experimentally determined relationship between the configurations of two molecules, even though we may not know the absolute configuration of either.

Title: Re:Absolute and Relative Configurations
Post by: movies on October 19, 2004, 10:05:25 PM

Okay, good.

So for one, suppose you had a molecule and you knew the relative configuration of two of the groups.  What difference would it make if you knew the absolute configuration?

Title: Re:Absolute and Relative Configurations
Post by: FictionDurden on October 19, 2004, 10:53:38 PM

You wouldn't have to do an experiment?

Title: Re:Absolute and Relative Configurations
Post by: movies on October 20, 2004, 11:56:46 AM

You would.  But what is a very simple experiment that you could do to distinguish a molecule that has an absolute configuration from a molecule where you only know the relative configuration (if the two molecules are the same otherwise).