 The X-ray diffraction bond length values are 139.1 pm for the [6,6] bond and 145.5 pm for the [5,6] bond.C60 fullerene has 60 π electrons but a closed shell configuration requires 72 electrons.The fullerene is able to acquire the missing electrons by reaction with potassium to form first the salt and then the In this compound the bond length alternation observed in the parent molecule has vanished.