In chemical terms, the most common cause of chirality in a molecule is an atom that is bonded to four different groups. This atom with four different groups is called a stereocenter (or stereogenic center).
For example, consider the following molecule.
This molecule has no plane or center of symmetry, so it is a chiral
molecule. The third
carbons from the left are stereocenters
, because they are each bonded to four different groups. The hydrogens have been drawn in here to make it easier to determine that there are four different groups; this will not be done in future sections.
molecule that has stereocenters
can have multiple three-dimensional representations. In general, a chiral
molecule with stereocenters
How many different forms does the above molecule have?
This molecule has four
different forms. It has two
stereocenters, so it has 22
, or four
, different forms.