Geometrical isomers occur in alkenes when both carbon atoms forming the double bond are attached to 2 different groups. It has a restricted rotation.
- When the carbon atom is attached to 4 different groups
- It is asymmetric but cannot be superimposed on its mirror image
- The mirror images cannot be interconverted without breaking covalent bonds
- 2 non-superimposable images are optical isomers or enantiomers