VAPOR-PRESSURE OF C-60 BUCKMINSTERFULLERENE

The equilibrium pressures over C-60 were measured over a large temperature range, 730-990 K, by the torsion effusion and Knudsen effusion methods. The data obtained are well represented by the following selected linear equation: log(p/kPa) = (8.28 +/- 0.20) - (9154 +/- 150)/T. Considering the vapor phase constituted by only C-60(g), the sublimation standard enthalpy of this compound, Delta(sub)H(0)(298) = 181 +/- 2 kJ mol(-1), as derived by second- and third-law elaboration of the experimental data, is proposed. Considerations on free energy functions of the solid C-60 are also reported.