Dissociation pressure and standard dissociation enthalpy of RuO2.

The absolute dissociation oxygen pressure above RuO2 was measured by the torsion-effusion method. By a least-squares treatment of the data, the following equation for the temperature dependence of these pressures in the temperature range 986-1221 K was selected: log(p/kPa)= (10.52±0.30) - (15143±400)/T. By treating the data by the second- and third-law methods the standard enthalpy associated with the dissociation of RuO2, ?disH°(298 K)=310±4 kJ mol-1, was derived. A comparison with literature data is also reported.