THERMODYNAMICS OF C-60 IN PURE O2, N2, AND AR

Fcc C60 crystals exposed to pure O2 are converted to carbon-oxygen adducts at approximately 200-degrees-C. The carbon-oxygen species decompose into CO and CO2 gases at a higher temperature, approximately 400-degrees-C. The total heats of oxidation of C60 are determined by calorimetry to be approximately 53 kcal/mol. The activation energy for the oxidation is 58.2 kcal/mol. The C60 powders in inert gases such as N2 and Ar sublime at approximately 600-degrees-C. A method is derived to determine the heats of sublimation from thermogravimetric analysis. The heat of sublimation of C60 powders in pure N2 or Ar is found to be greater-than-or-similar-to 39 kcal/mol.