We analyze the stabilization and the exact controllability of a third order linear equation in a bounded interval. That is, we consider the following equation:
iu_t+i\gamma u_x+ \alpha u_{xx} + i\beta u_{xxx} =0,
where u=u(x,t) is a complex valued function defined in (0,L)\times(0,+\infty) and \alpha , \beta and \gamma are real constants. Using multiplier techniques, HUM method and a special uniform continuation theorem, we prove the exponential decay of the total energy and the boundary exact controllability associated with the above equation. Moreover, we characterize a set of lengths L , named \mathcal{X} , in which it is possible to find non null solutions for the above equation with constant (in time) energy and we show it depends strongly on the parameters \alpha , \beta and \gamma .