Organic Chemistry Solutions: #2
2. Five and six-membered rings of carbon atoms are favored (i.e. more stable) over rings that have other numbers of atoms. Explain why.
Because electrons repel each other and wish to be as far apart as possible, we can deduce the following:
Because of each angle of a regular polygon is 180o - (360o /n) where n is the number of sides (360o /n is the central angle and each central angle defines an isoceles triangle and the sum of the angles in a triangle is 180o), we can deduce the following:
*note: this is not taking into account the especially stable "chair" conformation that cyclohexane can adopt.
From these tables, it is clear that five and six-membered rings are the ones that come the closest to the preferred bond angles of carbon in any of its hybridization states.