What is geometric isomerism?

Geometrical isomerism or Cis–trans isomerism is a type of isomerism where two or more molecules have the same molecular formula but different spatial arrangements of the atoms. 

The conditions for geometrical isomerism

1. The molecules must have double or triple bonds, a ring structure.

2. The atoms or groups of atoms attached to the double or triple bonds or the ring structure must be different. 

3. The molecules must have restricted rotation around the double or triple bonds or the ring structure or single bond for substituted biphenyls. 

4. The molecules must have different spatial arrangements of the atoms.

What are geometrical isomers types?

There are two types of geometrical isomers-

1. Cis isomers
2. Trans isomers.

What causes geometric isomers?

Geometric isomers are caused by the presence of a double or triple bond in a molecule, or a ring structure, which restricts the rotation of the atoms or groups of atoms attached to the double or triple bond or the ring structure. This restriction in rotation results in molecules having different spatial arrangements of the atoms, which are known as geometric isomers.

Do geometric isomers have the same physical properties?

No, geometric isomers do not have the same physical properties. For example, cis-but-2-ene and trans-but-2-ene have different boiling points, with cis-but-2-ene having a boiling point of 3.7°C and trans-but-2-ene having a boiling point of 0.8°C.

Why do alkanes not show geometrical isomerism?

Alkanes do not show geometrical isomerism because they do not have double or triple bonds or a ring structure, which are required for geometrical isomerism. Alkanes are composed of only single bonds, which allow free rotation around the bond and therefore do not restrict the spatial arrangement of the atoms.