* This theory put forth by Sache & Mohr to explain the relative stability of cyclohexane & higher cycloalkanes.
* According to this theory the stability of cyclohexane & higher cycloalkanes is possible when ring is strain theory.
* The strain free ring is possible if all the carbon atoms in the ring of cycloalkanes are not forced in one plane.
* As a result of this the ring attains ideal bond angle 109o28' . Which gives sustainable stability to cyclohexane & higher cycloalkanes. Ex: Stability of cyclohexane.
* When the ring of cyclohexane is folded or puckered leads into formation of two puckered conformations such as chair form & Boat form.
* The chair form as well as the Boat form are stable due to non-plannar geomentry & attain ideal bond, bond angle 109o28'.
* Further more the chair form is more stable than Boat form.
* In chair form four carbon atoms lie in central plane, one carbon atom appears above the central plane & one carbon atom lies below the central plane. Thus chair form is non-planner form & attains 109o28' bond angle.
* In addition to this six hydrogen atoms are attached to axial bonds & called axial hydrogen atoms, while six hydrogen atoms bonded to equatorial bonds called equatorial hydrogen atoms. It causes less strain in hydrogen atoms and carbon atoms.
* The axial bonds are perpendicular to the central plane & equatorial bonds are paralled to the plane.
* All forgoing facts can or release the strain in the ring. It results into stability of chair form of cyclohexane.
* In Boat form the four carbon atoms lie in central plane but remaining two carbon atom lie above the central plane. Hence forth at some extent in Boat form the strain is higher than chain form.
- H - axial bond
- H - equatoria bond
