91Ó°ÊÓ

Chair conformation structure for a six-membered ring is when atoms 2, 3, 5, and 6 lie in the same plane, atom one lies above the plane, and atom 4 lies below the plane.

Axial bonds are the bonds that are perpendicular or vertical to the ring plane. Equatorial bonds are approximately horizontal in the plane of the ring.

The energy difference between axial and equatorial conformations is due to steric strain caused by 1,3-diaxial interactions. The axial hydroxyl group on C1 is too close to the axial hydrogens three carbons away on C3 and C5, resulting in two times the steric strain.

One 1,3-diaxial interaction results in 2.1 kJ/mol increase in energy of axialcyclohexanol.

Hence, two such interactions give 4.2 kJ/mol.