Abstract
Using first-principles calculations and strain-energy methods, we investigate the elastic constants of the inorganic molecular crystal few-layer α-Sb(2)O(3), including stiffness constants (C (ij) ), bulk modulus (B), Young's modulus (E), shear modulus (G), and Poisson's ratio (ν). The study revealed that for few-layer α-Sb(2)O(3), the values of B and E consistently exceed those of G. For instance, in monolayer α-Sb(2)O(3), B = 22.00 N/m, E = 31.09 N/m > G = 12.02 N/m. Additionally, its elastic constants, apart from ν, increase nearly linearly with the number of layers. We further reveal that its unique elastic constants are collectively governed by weak intercage chemical bonds and intercage van der Waals (vdW) bonds within the plane. These findings establish a rigorous theoretical framework for elucidating the unique mechanical properties of α-Sb(2)O(3), reinforcing its significant role in dielectric and encapsulation applications while emerging as a candidate for flexible electronics. Furthermore, they offer new directions for fundamental research and the practical advancement of other inorganic molecular crystals.