# What energy difference is calculated for axial vs Equatorial conformations?

## What energy difference is calculated for axial vs Equatorial conformations?

3) Remembering that the axial conformation is higher in energy, the energy difference between the two conformations is ΔE = (E equatorial – E axial) = (0 – 2.4 kJ/mol) = -2.4 kJ/mol.

### What is the energy difference in kJ mol between axial and equatorial conformation of Ethyl cyclohexane?

So, the equatorial conformation is more stable than the axial by 7.28 kJ/mol. This energy difference is known as the A value and it varies depending on the axial group. The larger the group, the higher the energy difference.

What is the difference between Equatorial and axial?

Bonds to non-ring atoms with angles of about 90° to the ring plane are termed axial. Bonds to non-ring atoms which make only a small angle compared with the plane of the ring are termed equatorial.

Why is equatorial conformation more stable?

When the methyl group is in the equatorial position this strain is not present which makes the equatorial conformer more stable and favored in the ring flip equilibrium. The Newman projection of equatorial methylcyclohexane shows no such interactions and is therefore more stable.

## What is axial and equatorial position?

Axial and equatorial are types of bonds found in the chair conformation of cyclohexane. The chair conformation is the most stable conformation of cyclohexane. Axial positions are perpendicular to the plane of the ring and equatorial positions are around the plane of the ring.

### What is axial equatorial position?

What is equatorial and axial position?

The key difference between axial and equatorial position is that axial bonds are vertical while equatorial bonds are horizontal. The terms axial and equatorial are important in showing the actual 3D positioning of the chemical bonds in a chair conformation cyclohexane molecule.

Why do bulky groups prefer equatorial?

By being on the equatorial positions, bulkier groups are allowed to remain as away as possible and relieve the molecule from torsoinal strain, which otherwise (if these are on axial postions) parts of these bulkier groups are thrown closer to each other and may increase the torsional strain experienced by the molecule.

## What is the axial position?

What is Axial Position? Axial position is the vertical chemical bonding in the chair conformation of cyclohexane. Due to the minimized steric hindrance, the chair conformation is the most stable structure for the cyclohexane molecule. The axial position is perpendicular to the plane of the ring of cyclohexane.

### Is equatorial or axial more stable?

A conformation in which both substituents are equatorial will always be more stable than a conformation with both groups axial.

Which is the energy difference between axial and Equatorial conformations?

We quantify the energy difference between the axial and equatorial conformations as the A-value, which is equivalent to the negative of the ∆G°, for the equilibrium shown below. Therefore the A-value, or -∆G°, is the preference for the substituent to sit in the equatorial position.

How to calculate the energy of a conformation?

Table: Below is a table of A-values for some common substituents. This table allows us to estimate the actual energy differences between conformations with axial vs. equatorial substituents. However, in general, to stablize we simply place bigger groups equatorial.

## What is the percentage of equatorial conformation at 150°C?

Thus we can say that at 150°C, 88.8% of equatorial conformation and 11.2% of axial conformation exists in equilibrium. As we can see from the above calculations, as the temperature rises, the percentage contribution by equatorial conformation decreases, while that by axial conformation increases.

### Which is the axial position in a conformation?

In this type of conformation, there are two positions: axial and equatorial. Axial positions which perpendicular to the plane of the ring – these are highlighted in red on the diagram. The angles of these bonds are usually around 90˚.