in Organic Chemistry

Isomers (Part 2 of 2)

You can find the first part of this series here: Isomers (Part 1 of 2).


  • A molecule is chiral if it is not superimposable on it’s mirror image
  • Most chiral molecules can be identified by their lack of a plane, or centre of symmetry
  • Your hand for example, is a chiral object
  • The most common cause of chirality in a molecule is an atom that is bonded to four different groups
    • The atom that has 4 different groups is called the stereocenter


This molecule has 2 chiral centres. Two of the atoms have 4 different groups bonded to them

A chiral molecule that has stereocentres can have multiple three dimensional representations. In general, a chiral molecule with stereocenters has 2n different forms; where n = number of stereocenters in the molecule.


Diastereomers are stereoisomers that are not mirror images of one another and are non-superimposable on one another.


  • Not mirror images of one another ✓
  • Non-superimposable ✓

∴ They are diastereomers

Recommended Reading for Chemistry