Geometric Isomerism printable pdf download

Geometric Isomerism

C h e m g u i d e – a n s w e r s

GEOMETRIC ISOMERISM

H H

H C C H

The molecule on the left has a carbon-carbon single bond, with free rotation around that bond.

Geometric isomerism can only occur where bonds are locked into one position, as they are in the

right-hand molecule. There is no free rotation around the double bond, and so the chlorines could

be locked into one of two positions relative to each other:

That isn't possible in the other molecule, because the two chlorines can simply rotate around the

single bond from one position to another.

2. This is the only one which can have geometric isomers:

CHCH

Geometric isomers have to have two different groups at both ends of the double bond. All the other

structures have either two hydrogens or two methyl groups on one of the ends of the double bonds.

The geometric isomers are:

Geometric Isomerism