  The barriers standing against the formation of superheavy elements and their
consecutive $\alpha$ decay have been determined in the quasimolecular shape
path within a Generalized Liquid Drop Model including the proximity effects
between nucleons in a neck, the mass and charge asymmetry, a precise nuclear
radius and the shell effects given by the Droplet Model. For moderately
asymmetric reactions double-hump potential barriers stand and fast fission of
compact shapes in the outer well is possible. Very asymmetric reactions lead to
one hump barriers which can be passed only with a high energy relatively to the
superheavy element energy. Then, only the emission of several neutrons or an
$\alpha$ particle can allow to reach an eventual ground state. For almost
symmetric heavy-ion reactions, there is no more external well and the inner
barrier is higher than the outer one.
