Dissociation pressure and standard dissociation enthalpy of RuO2

The absolute dissociation oxygen pressure p above RuO2 was measured by the torsion-effusion method. By a least-square treatment of the data, the following equation for the temperature dependence of these pressures in the temperature (T) range 986–1221 K was selected: log(p)=(10.52±0.30)−(15,143±400)/T, where p is measured in kPa. By treating the data by the second- and third-law methods the standard enthalpy associated with the dissociation of RuO2 (310±4 kJ mol−1) was derived. A comparison with literature data is also reported.