I evaluated the elastic moduli (Young's modulus and shear modulus) and coefficient of thermal expansion (CTE) of single-layered graphene sheets (SLGS) based on FEM analysis. It is well known that due to the orientation of C-C bonds, the mechanical and thermal properties of the all the three types of graphene sheets varies. But I want to know the exact reason behind these variations in the elastic moduli and CTE of zigzag, armchair and chiral SLGS. Thanks in advance.