Cyclopentane (larger view)

Cyclopentane (larger view)

 

(How to manipulate JSmol structures)

Cyclopentane

The fourth carbon in cyclobutane is ~25^o out of the plane of the other three carbon atoms thereby relieving some of the the C-H bond eclipsing. (The feet of four-legged stools do not have to lie in a plane.Place three carbon atoms in a plane. View down a C-C bond and convince yourself that C-H bond eclipsing is reduced.

Cyclopentane has an envelope conformation. Find the carbon atom that is the envelope "flap". Click here.