AN FT-IR AND TGA STUDY OF THE THERMAL-OXIDATION OF C-60

The thermal stability of C60 in pure oxygen has been investigated by i n-situ FT-IR and thermogravimetric analysis (TGA). It is shown that at temperatures of about 250-degrees-C. the C60 loses its spherically sy mmetric structure and is oxidized to an anhydride type species. The an hydride on exposure to air is converted to an acid which however rever ts to the anhydride on heating in a nitrogen or oxygen atmosphere. On heating beyond 250-degrees-C, the C60 is completely oxidized probably to CO and CO2, but this complete oxidation appears to take place in tw o stages with the anhydride part of the molecule getting oxidized firs t. It is postulated that the lower oxidative stability of C60 compared to graphite is probably due to the greater reactivity towards oxygen of the pentagon-hexagon junction, compared to the hexagon-hexagon junc tion, present in C60.