Cyclohexane

Cyclohexane is the cyclic alkane ${\mathrm{C}}_6{\mathrm{H}}_{12}$. Its preferred chair conformation allows near-tetrahedral bond angles and largely staggered neighboring bonds.

Ring flips exchange axial and equatorial positions. Consequently a substituent can retain its up/down orientation while changing the steric interactions that determine conformational preference and reaction accessibility.