- Optical isomerism arises because of the different ways in which you can arrange four groups around a carbon atom.
- It's a type of stereoisomerism.
- Four single bonds around a carbon atom are arranged tetrahedrally.
- When four different atoms or groups are attached to thesefour bonds, the molecule can exist in two isomeric forms.
- The two isomers are mirror images of each other - the mirror image and the original molecule are non-superimposable.
- Optical isomers are also called enantiomers.
- Molecules that can form optical isomers are called chiral molecules.
- A carbon atom that is bonded to four different groups is called a chiral centre.
- The proteins in our bodies are made from only one enantiomer of each amino acid - these are the L-enantiomers.
- 'CORN' rule: COOH, R, NH2
- L-enantiomers have this sequence when you look down the C-H bond and go clockwise.
- D-enantiomers have this sequence when you look down the C-H bond and go anticlockwise.
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