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The simplest examples of angle strain are small cycloalkanes such as cyclopropane and cyclobutane. Ring strain energy can be attributed to the energy required for the distortion of bond and bond angles in order to close a ring. [3] Ring strain energy is believed to be the cause of accelerated rates in altering ring reactions.
There are situations where seemingly identical conformations are not equal in strain energy. Syn-pentane strain is an example of this situation. There are two different ways to put both of the bonds the central in n-pentane into a gauche conformation, one of which is 3 kcal mol −1 higher in energy than the other. [1]
Castigliano's method for calculating displacements is an application of his second theorem, which states: If the strain energy of a linearly elastic structure can be expressed as a function of generalised force Q i then the partial derivative of the strain energy with respect to generalised force gives the generalised displacement q i in the direction of Q i.
The strain energy in the form of elastic deformation is mostly recoverable in the form of mechanical work. For example, the heat of combustion of cyclopropane (696 kJ/mol) is higher than that of propane (657 kJ/mol) for each additional CH 2 unit. Compounds with unusually large strain energy include tetrahedranes, propellanes, cubane-type ...
In organic chemistry, transannular strain (also called Prelog strain after chemist Vladimir Prelog) is the unfavorable interactions of ring substituents on non-adjacent carbons. These interactions, called transannular interactions, arise from a lack of space in the interior of the ring , which forces substituents into conflict with one another.
In contrast, the strain energy of cyclobutane is specific to the parent compound, with their new corrections, it is now possible to predict Δ f H° values for strained ring system by first adding up all the basic group increments and then adding appropriate ring-strain correction values. The same as ring system, corrections have been made to ...
Energy principles in structural mechanics express the relationships between stresses, strains or deformations, displacements, material properties, and external effects in the form of energy or work done by internal and external forces. Since energy is a scalar quantity, these relationships provide convenient and alternative means for ...
where is the force (positive in compression), is the total surface energy of both surfaces per unit area, and is the equilibrium separation of the two atomic planes. The Bradley model applied the Lennard-Jones potential to find the force of adhesion between two rigid spheres.