Mechanics Applied to Alkanes and Cycloalkanes

If we assume that there are certain ideal values for bond angles, bond distances, and so on, it follows that deviations from these ideal values will destabilize a particular structure and increase its potential energy. This increase in potential energy is referred to as the strain energy of the structure. Other terms include steric energy and steric strain. Arithmetically, the total strain energy (EJ of an alkane or cycloalkane can be considered as 

Eangie bending Is the Strain that results from the expansion or contraction of bond angles from the normal values of 109.5° for sp hybridized carbon. 

Evan der waais s the Strain that results from non-bonded interactions.  

Nonbonded interactions are the forces between atoms that aren t bonded to one another they may be either attractive or repulsive. It often happens that the shape of a molecule may cause two atoms to be close in space even though they are separated from each other by many bonds. Induced-dipole/induced-dipole interactions make van der Waals forces in alkanes weakly attractive at most distances, but when two atoms are closer to each other than the sum of their van der Waals radii, nuclear-nuclear and electron-electron repulsive forces between them dominate the Evan der waaistei m-The resulting destabilization is called van der Waals strain. 

C—H bond distances are distorted from their ideal values of 153 pm and 111 pm, respectively. 

Evan der Waals S the Strain that results from nonbonded interactions.  

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Molecular Mechanics Applied to Alkanes and Cycloalkanes 107 Enthalpy, Free Energy, and Equilibrium Constant 118... 

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