  We have investigated the temperature dependence of the linear thermal
expansion along the hexagonal c axis ($\Delta L$), in-plane resistivity
($\rho$), and specific heat ($C_p$) of the topological insulator Sb$_2$Te$_3$
single crystal. $\Delta L$ exhibits a clear anomaly in the temperature region
204-236 K. The coefficient of linear thermal expansion $\alpha$ decreases
rapidly above 204 K, passes through a deep minimum at around 225 K and then
increases abruptly in the region 225-236 K. $\alpha$ is negative in the
interval 221-228 K. The temperature dependence of both $\alpha$ and $C_p$ can
be described well by the Debye model from 2 to 290 K, excluding the region
around the anomaly in $\alpha$.
