Atomic CN Reduction

The CN of an atom in a highly curved surface is lower than that of an atom at a flat surface. For a negatively curved surface (such as the inner side of a pore or a bubble), the CN is greater than that of a flat surface. Therefore, from the atomic CN imperfection point of view, there is no difference in nature between a nanosolid, a nanosized pore, and a flat surface. This premise extends to the structural defects or faults such as voids surrounding which atoms experience a CN loss with respect to the ideal bulk standard of 12. 

CN imperfection is irrespective of the bond nature or the crystal structure. For example, the CN of an atom in diamond or silicon is 12 as the diamond structure is an interlock of two fee unit cells. 

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These expressions indicate that the mechanical work hardening by compression or by the compressive strain will shorten and strengthen but the thermal vibration or the tensile strain will elongate and weaken the bond. Atomic CN reduction shortens and strengthens the bond, according to the BOLS correlation. The generalized form indicates that one can consider all the stimuli either individually or collectively, depending on the experimental conditions. 

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