Dr. Kenneth C. McGill
The number of carbon atoms bonded in the ring of a cycloalkane has a large effect on its energy. A molecule's energy has a vast impact on its stability. Determining the most stable form of a molecule is a useful technique in the world of chemistry. One of the major factors that influence the energy (stability) of cycloalkanes is the molecule's ring strain. Ring strain is normally viewed as being directly proportional to the instability of a molecule. It is defined as a type of potential energy within the cyclic molecule, and is determined by the level of "strain" between the bonds of cycloalkanes. For example, propane has the highest ring strain of all cycloalkanes. Each of propane's carbon atoms is sp3-hybridized. The normal bond angle of sp3-hybridized carbons (tetrahedral arrangement) is 109.5°; however, in cyclopropane, the bond angles are approximately 60°. This large deviation from the normal bond angle causes cyclopropane to exhibit a high level of angle stain, which is the source of its ring strain.
Hobbs, Brad A.
"Comparing Models for Measuring Ring Strain of Common Cycloalkanes,"
The Corinthian: Vol. 6, Article 4.
Available at: https://kb.gcsu.edu/thecorinthian/vol6/iss1/4