Draw the three distinct geometric isomers of 2,4-hexadiene.

i can draw what it is giving. but i do not get what the geometric isomers are? if you drew it a different way wouldnt that change the name?

Geometric isomers are a type of stereoisomers that have the same molecular formula and connectivity but differ in the arrangement of atoms in space. In the case of 2,4-hexadiene, the geometric isomers arise due to the presence of a double bond and the different arrangements of the substituent groups on either side of the double bond.

Here are the three distinct geometric isomers of 2,4-hexadiene:

1. Trans,trans-2,4-hexadiene: In this isomer, both methyl groups are on opposite sides (trans configuration) of the double bond. The structure can be represented as:

H H H H
| | | |
H-C-C-C=C-C=C-C-H
| | | |
H H H H

2. Cis,trans-2,4-hexadiene: In this isomer, one methyl group is on the same side (cis configuration), while the other methyl group is on the opposite side (trans configuration) of the double bond. The structure can be represented as:

H H H H
| | | |
H-C-C-C=C-C=C-C-H
| / |
H H H

3. Trans,cis-2,4-hexadiene: In this isomer, one methyl group is on the opposite side (trans configuration), while the other methyl group is on the same side (cis configuration) of the double bond. The structure can be represented as:

H H H H
| | | |
H-C-C-C=C-C=C-C-H
| \ |
H H H

Each of these isomers has a different arrangement of atoms in space, resulting in distinct compounds with unique physical and chemical properties.

To understand the concept of geometric isomers, it is important to consider the concept of geometric isomerism in organic chemistry. Geometric isomerism arises from the restricted rotation around double bonds in molecules. In compounds with double bonds, the arrangement of substituents or groups on either side of the double bond can differ, giving rise to different geometric isomers.

In the case of 2,4-hexadiene, it has two double bonds: one between carbon 2 and carbon 3, and the other between carbon 4 and carbon 5. The three distinct geometric isomers of 2,4-hexadiene are known as cis-cis, cis-trans, and trans-trans isomers. Let's go through each of them.

1. Cis-Cis Isomer:
In this isomer, both double bonds have the same arrangement of substituents on the same side of the double bond. The prefix "cis" means "same side." To draw the cis-cis isomer, you can draw two parallel lines to represent each double bond and place the substituents accordingly, making sure they are on the same side of their respective double bonds.

2. Cis-Trans Isomer:
This isomer has one double bond with the substituents on the same side and the other double bond with the substituents on the opposite side. The prefix "cis" still applies to the double bond with the substituents on the same side, while "trans" is used for the double bond with substituents on opposite sides.

3. Trans-Trans Isomer:
In this isomer, both double bonds have the substituents arranged on the opposite sides. The prefix "trans" means "across" or "opposite sides."

The arrangement of substituents on the double bonds give each isomer its unique name and differentiates them from one another. It is crucial to properly position the substituents around the double bonds to represent the correct geometric isomers.

When drawing different geometric isomers, changing the arrangement or orientation of the substituents around the double bond will indeed result in a different isomer with a different name. Therefore, it is essential to consider the arrangement of groups on both sides of the double bond when identifying geometric isomers.

A good discussion of isomers AND the drawings of the three isomers of 2,4-hexadiene.

http://www.organicchemistry.com/stereoisomerism-of-organic-molecules-configurational-isomers/