= Axial and equatorial bonds
In a <chair conformation> of <cyclohexane>, axial bonds point approximately parallel to the ring's threefold axis, alternating up and down around the ring. Equatorial bonds point outward around its perimeter, also alternating in their up/down relationship to the ring.
A ring flip exchanges axial and equatorial positions but preserves a substituent's up or down orientation. Thus axial does not mean up, and equatorial does not mean down. In methylcyclohexane the equatorial methyl conformation is favored because an axial methyl group has unfavorable close contacts with axial substituents on carbons three and five.<Organic Chemistry by John McMurry>[§§4.6–4.7, ring flips and monosubstituted cyclohexanes]{ref}
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