  We predict a molecular vibrational state in the cold binary fission of
$^{252}$Cf using a simple decay cluster model. The Hamiltonian of two even-even
fragments in the pole-pole configuration is built in the same fashion as that
for the dinuclear molecule formed in heavy-ions collisions. The interaction
between the two fragments is described by the double-folding M3Y potential. The
spectrum of the butterfly vibrations is derived and its dependence on fragments
deformation and mass-assymetry is discussed. Some experimental implications are
commented.
