Calculated properties of C60 isomers and fragments

MNDO calculations have been carried out for three C60 isomers, buckminsterfullerene (Ih), graphitene (D6h), and a planar ring (D60h). Buckminsterfullerene is 880.2 kcal mol−1 more stable than the ring structure while graphitene is 648.7 kcal mol−1 more stable (1 kcal mol−1 = 4.184 kJ mol−1). Optimized geometric parameters and orbital energies are also reported. A novel mechanism for formation of the Ih structure is presented which involves a minimum of rearrangement.