Theoretical Model Upper Limit on The Lattice Parameter of Doped C60   Solid
  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. 
V.K. Jindal