In a molecule, strain energy is released when the constituent atoms are allowed to rearrange themselves in a chemical reaction or a change of chemical conformation in a way that:
- angle strain,
- torsional strain,
- ring strain and/or steric strain,
- Allylic strain, and
- pentane interference
are reduced. The external work done on an elastic member in causing it to distort from its unstressed state is transformed into strain energy which is a form of potential energy. 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) per methylene unit. Compounds with unusually large strain energy include tetrahedranes, propellanes, cubanes, fenestranes and cyclophanes.
Famous quotes containing the words strain and/or energy:
“Realistic about how much one person can accomplish in a given day, women expect to have to make some trade-offs between work and family. Families, however, have absorbed all the stress and strain they possibly can. The entire responsibility for accommodation is taking place on the home side of the equation.”
—Deborah J. Swiss (20th century)
“After the planet becomes theirs, many millions of years will have to pass before a beetle particularly loved by God, at the end of its calculations will find written on a sheet of paper in letters of fire that energy is equal to the mass multiplied by the square of the velocity of light. The new kings of the world will live tranquilly for a long time, confining themselves to devouring each other and being parasites among each other on a cottage industry scale.”
—Primo Levi (1919–1987)