  The results on the lattice instability, invoked by applying a negative
pressure on pure C60 solid, are described. The results of such a calculation
are used to correlate the experimentally achieved results on the
superconducting transition temperature Tc by doping C60 with alkali metals. A
simple model had been used already to interpret the bulk, structure and
thermodynamic properties Of C60 solids. As a result of this calculation an
upper limit on the lattice parameter results which is around 14.5A and is a
suggestion of an upper limit of Tc as well in doped C60.
