2-butene: Geometrical isomerism : CH3 -CH = CH – CH3
1. Geometrical isomers are the stereoisomers which have different arrangement of groups or atoms around a rigid framework of double bonds. This type of isomerism occurs due to restricted rotation of double bonds or about single bonds in cyclic compounds.
2. In 2-butene, the carbon-carbon double bond is sp2 hybridised. Due to presence carbon-carbon double bond it lock the molecule in one position. Hence, rotation around C = C bond is not possible.
3.
cis 2-butene
trans 2- butene
4. These two compounds are termed as geometrical isomers and are termed as cis and trans form.
5. The cis-isomer is the one in which two similar groups arc on the same side other double bond. The trans-isomer is that in which two similar groups are on the opposite side of the double bond. Hence, this type of isomerism is called cis-trans isomerism.
