Elastic Constants of Few-Layer α‑Sb₂O₃ from First-Principles Calculations: Insights into Mechanical Properties

Using first-principles calculations and strain-energy methods, we investigate the elastic constants of the inorganic molecular crystal few-layer α-Sb₂O₃, 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-Sb₂O₃, the values of B and E consistently exceed those of G. For instance, in monolayer α-Sb₂O₃, 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-Sb₂O₃, 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.