Knowledge Bank

The spectra of organic compounds under stress by mechanical deformation show that the deformation is roughly correlatable with crystal class and crystal energy. Some compounds give spectra which in KBr pellets are nearly identical to solution spectra, thus indicating existence of a molecularly dispersed state. Stress relaxation in KBr pellets can be followed by changes in the infrared spectra. Polymorphism and second order transitions can be induced by mechanical vibration, precipitation from solvents, or by compression in KBr. The plastic flow in KBr is sufficiently different from the flow in KC1 that crystal deformation will frequently occur in one and not the other.