The chair conformation of cyclohexane is always more stable than the boat conformation due to minimized steric strain and torsional strain.

The chair form of cyclohexane is more stable because it lets all bonds be nearly perfect tetrahedral, so there is little torsional strain and no eclipsing interactions. In the chair, each C–C bond is staggered and the ring angles are close to 109. 5°, so the atoms are far enough apart to avoid steric clashes. By contrast, the boat shape forces several eclipsed bonds and bends the ring, creating both torsional strain and steric crowding between the “flagpole” atoms. For example, in the boat the two “flagpole” carbons are only about 2.