What is the difference between enantiomers and chirals?

1 Answer
Jan 24, 2016

A chiral centre is (typically) a carbon with 4 different substituents. Such a carbon is a chiral centre, which exhibits optical isomerism in that it can form a pair of optical isomers, a pair of ENANTIOMERS.


So imagine a carbon centre with 4 distinct substituents, i.e. #CR_1R_2R_3R_4# (the #R# can be ethyl, methyl, halogen, oxygen, as long as they are different. Because there are 4 different substituents attached to this carbon, this is a CHIRAL centre, capable of generating a pair (i.e. 2) of enantiomers, non-superposable mirror images.

Think of your left hand and your right hand. These are a pair of optical isomers, structurally identical, but which cannot be superimposed upon each other (or upon the hands of your identical twin!).

If you have just come across these terms, I urge you to get a set of models; you could also use blobs of plasticene and toothpicks. This helps to visualize the isomerism. Note that around a chiral carbon, the interchange of ANY 2 substituents results in the enantiomer. You have to able to represent this on the printed page.