Chapter 4, Problem 4.28P

Interpretation Introduction

Interpretation:

For the given Newman projection of cyclohexane, all the $\text{C-H}$ bonds which are axial and equatorial are to be identified.

Concept introduction:

Newman projection is a two-dimensional representation of a molecule viewed down the bond of interest. In a Newman projection, two atoms directly connected by the bond of interest are shown explicitly. The nearer atom is depicted as a point while the more distant atom is depicted as a circle. Bonds of the front (nearer) atom converge at the point whereas bonds to the back atom connect to the circle. The bond of interest is not visible; instead it must be imagined as connecting the front and the back carbon atoms. In cyclohexane, all six carbon atoms are completely indistinguishable, but there are two different types of hydrogen atoms; six hydrogen atoms occupy the equatorial positions and six occupy the axial position. Each carbon atom in cyclohexane is bonded to one of each. The basic framework of chair form of cyclohexane is:

Axial bonds are alternate up and worn around the ring (highlighted in red). Equatorial bonds are alternate slightly up and down around the ring (highlighted in blue).

In the rotational conformations, the bonds which are up remain up and the bonds which are down remain down.