Fig. 3. gem-Dihalocyclopropane undergoes a force-induced ring opening to a 2,3-dihaloalkene, and serves as a platform to quantitatively compare mechanical reactivity as a function of force-free reactivity, the geometry of attachment, and polymer backbone effects. The change in length along the vector of applied force on going from reactant to transition state, Δx, is depicted here as a local change, but must be considered in the context of where the force is applied.