Question

What is eclipsed conformer in Newman projections?

Answer 1

The eclipsed conformer in a Newman projection is the arrangement in which the dihedral angles between the front and back bonds are 0 °.

Explanation:

The bonds on the back carbon are directly behind the bonds on the front carbon.

In the eclipsed conformation of propane, the `"C-H"` bonds on the back carbon are directly behind the front `"C-H"` bonds. The rear `"C-H"` bonds are "eclipsed" by those in front.

Also, the `"C-CH"_3` bond eclipses the `"C-H"` bond behind it.

We say that the dihedral angle between the front and rear bonds is 0 °.