The chair conformation is a low-energy nonplanar arrangement of the six-membered cyclohexane ring. Its carbon-carbon bonds are approximately staggered and its bond angles remain close to tetrahedral values, reducing torsional and angle strain.
Each ring carbon has one axial and one equatorial substituent position. A ring flip exchanges these positions while retaining whether each substituent points to the same or opposite side of the ring. Bulky substituents commonly prefer equatorial positions because this reduces unfavorable 1,3-diaxial interactions, making chair analysis useful for predicting conformational populations and reaction geometry.[ref]
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