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The standard molar enthalpy of combustion of hydrofullerene C 60 H 36 was determined by static bomb calorimetry, ∆ c H°m ) -(29769 ( 25) kJ‚mol -1 . Using this result and the standard molar enthalpy of sublimation, ∆ sub H°m ) (175 ( 5) kJ‚mol -1 , the values of the standard molar enthalpies of formation of C 60 H 36 in the crystalline and gaseous states were calculated: ∆ f H°m(C 60 H 36 , cr) ) (1013 ( 26) kJ‚mol -1 and ∆ f H°m(C 60 H 36 , g) ) (1188 ( 26) kJ‚mol -1 . The enthalpy of reaction C 60 H 36 (g) ) C 60 (g) + 36 H(g) was found to be (9196 ( 30) kJ‚mol -1 , or (255.4 ( 0.8) kJ‚mol -1 per one C-H bond. The enthalpy of reaction C 60 F 36 (g) + 36 H(g) ) C 60 H 36 (g) + 36 F(g) was calculated, ∆ r H°m ) (1421 ( 203) kJ‚mol -1 , or (39.5 ( 5.6) kJ‚mol -1 per one H atom. The enthalpies of bond breaking and of F to H replacement were compared with the analogous values in some other organic compounds.

The standard molar enthalpy of combustion of fluorofullerene C 60 F 36 was determined by rotating-bomb calorimetry, ∆ c H°m ) -24692 ( 199 kJ‚mol -1 . Using this result and the standard molar enthalpy of sublimation, ∆ sub H°m ) 139 ( 8 kJ‚mol -1 , the values of the standard molar enthalpies of formation of C 60 F 36 in the crystalline and gaseous states were found to be -5362 ( 201 kJ‚mol -1 and -5223 ( 201 kJ‚mol -1 , respectively. The enthalpy of reaction C 60 F 36 (g) ) C 60 (g) + 36F(g) was calculated, ∆ r H°m(298.15 K) ) (10617 ( 202) kJ‚mol -1 , or 294.9 ( 5.6 kJ‚mol -1 per one C-F bond. The comparison with the enthalpy of reaction C 60 F 48 ) C 60 (g) + 48F(g), ∆ r H°m(298.15 K) ) 287.5 ( 3.5 kJ‚mol -1 per C-F bond leads to a preliminary conclusion that C-F bond enthalpy decreases with amount of F atoms attached to the fullerene cage.

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