What is the most stable conformation of cyclohexane?

The most stable conformation of cyclohexane is the chair conformation. This stability arises from several factors related to the spatial arrangement of the carbon atoms and the hydrogen atoms attached to them.

In the chair conformation, cyclohexane allows for the most favorable bond angles (approximately 109.5 degrees) that correspond to the tetrahedral geometry of sp^3-hybridized carbon atoms. This geometry minimizes steric strain, as the hydrogen atoms are positioned farthest apart, reducing 1,3-diaxial interactions that would otherwise occur in other forms.

Additionally, the chair conformation avoids torsional strain, which is a result of eclipsing interactions between atoms. In contrast, other conformations like the boat or totally eclipsed arrangements introduce increased steric hindrance and torsional strain, leading to higher energy states and therefore lower stability compared to the chair form. The planar conformation of cyclohexane is also less favorable, as it introduces angle strain and is not conducive to the preferred tetrahedral angles.

In summary, the chair conformation of cyclohexane is distinguished by its strain-free environment, making it the most stable and favorable of the various conformations.