Sublimation of the endohedral fullerene Er3N@C80

The heat of sublimation of the endohedral metallofullerene Er3N@C-80 was measured via Knudsen effusion mass spectrometry. The large molecule consists of a C-80 fullerene cage which is stabilized by a complex of three erbium atoms bounded to a nitrogen atom and has a mass of 1475 amu. The mass spectrum at a temperature of 1045 K and the relative intensities of the thermal fractions of Er3N@C-80 are provided. We also discuss possible thermal decomposition processes for these particles. By measuring the quantity of evaporated molecules in thermal equilibrium using a quadrupole mass spectrometer in a temperature range between 782 K and 1128 K, a value for the sublimation enthalpy of Delta H-sub = 237 +/- 7 kJ mol(-1) is obtained via the second-law method.