It is the only planar cycloalkane. It is characterized by a large angular stress due to bond angles well below 109.5º. The sp ³ of the carbons that make up the cycle overlap by curving outward, to decrease tension. Giving rise to curved links called banana links.

Cyclopropane has three hydrogens facing each other (eclipsed hydrogens), which further increase the tension of the molecule.






It is for this reason the most unstable cycloalkane. {alert} Molecular model of cyclopropane {/alert}