▎ 摘　　要

In this paper, by an analogy with the 3D-systems, and because of the analysis of the dimensionalities of the variables involved, an expression is derived in the quasi-harmonic approximation that allows one to estimate the linear thermal expansion coefficient for a single-layered graphene (which represents the 2D-system) at the temperatures close to the room temperature. It is shown that compared to the other methods to evaluate the thermal expansion coefficient of graphene at the room temperatures (the molecular dynamics method or the method of approximation with the aid of nonequilibrium Green's function, for which the obtained results differ from experimentally measured values at least by 7%), the accuracy of the value obtained by the suggested expression is 5 times higher (the discrepancy from the measured values figures up to 1.4%).