Conformation of Ethane Explained in 10 Slides

BY Team Aakash Byju's

CBSE Organic Chemistry

 Ethane is a chemical compound with the chemical formula C₂H₆.

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There are 3 carbon atoms bonded together and each with  3 hydrogen atoms. In general, we can show its structure as:

We use Newman Projections to study the types of conformations of ethane. As it helps to visualise the side view of 3-D structure of ethane.

 3 hydrogens associated with the front carbon are aligned with 3 hydrogens of the back carbon.

Eclipsed Conformation of Ethane:

Consider just one hydrogen on the upper side of both carbons. Since they both are aligned, the dihedral angle is 0 degree.

3 hydrogens associated with front carbon are not aligned with 3 hydrogens associated with back carbon.

Staggered Conformation of Ethane:

In staggered conformation, all C-H bonds on the front carbon are positioned at dihedral angles of 60° relative to the C-H bonds on the back carbon.

The front view of both eclipsed and staggered conformation of ethane rotating one of the carbon is shown below:

The most stable conformation for ethane is staggered conformation as six C-H bonds are as far away as possible from each other.

Experiments confirm that there is a barrier of 12 kJ per mol or 2.9kCal per mol to rotate in ethane.