DETERMINATIONS OF COMBUSTION AND FORMATION ENTHALPIES OF C-60 AND C-70

By using a micro-bomb calorimeter, the standard enthalpies of combusti on of C-60 and C-70 have been determined to be -(25947.1 +/- 8.5) and -(29956.1 +/- 8.9) kJ/mol respectively. A g. l. c. analysis indicated that the amounts of residual organic solvents in the samples were very small, and their effects on the final results were negligible. The en ergy of combustion of C-60 determined in this work is in agreement in the uncertainty interval with that determined by means of traditional calorimeter using macro amount of sample. The enthalpies of formation of these two substances have been derived. The strain energies in the molecules of C-60 and C-70 were estimated by a bond energy scheme and by using corannulene as the model compound, the results estimated from different methods are very close.