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.