Thermal Expansion Study as a Tool to Understand the Bending Mechanism in a Crystal

Here for the first time thermal expansion study has been explored to understand the bending mechanism in crystals. Dimorphic 4-chlorobenzonitrile has been chosen to demonstrate it. We have postulated that some of the structural features of the concave and convex sides of the bent crystal would resemble thermally compressed and expanded crystal structures respectively in the expansion–contraction bending mechanism. In this mechanism it has been shown that the strain is proportional to the thickness of the crystal and inversely proportional to the radius of the curvature of the bent crystal. On the other hand, in the case of slip plane mechanism, the amount of sliding of a layer with respect to its neighbor at the two terminals of the crystal is proportional to the arc angle of the bent crystal and the distance between the two consecutive slip planes