In
chemistry, a
molecule experiences
strain when its
chemical structure undergoes some stress which raises its
internal energy in comparison to a strain-free reference compound. The internal energy of a molecule consists of all the energy stored within it. A strained molecule has an additional amount of internal energy which an unstrained molecule does not. This extra internal energy, or
strain energy, can be likened to a compressed
spring. Much like a compressed spring must be held in place to prevent release of its
potential energy, a molecule can be held in an energetically unfavorable conformation by the
bonds within that molecule. Without the bonds holding the conformation in place, the strain energy would be released.