Vaporization of Compounds and Alloys at High Temperatures. Part XXVI. Mass Spectrometric Study of the Vaporization of Lead Monoxide. The Dissociation Energy of Pbo

摘要

The composition of the vapor in equilibrium with lead oxide (yellow rhombic form) in the temperature interval 1000-1150K was determined mass spectrometrically. The predominant species are PbO, Pb2O2, Pb3O3 and Pb4O4. From the partial PbO pressure measured here and that based on a reinterpretation of the literature data, when taking the presence of the polymers into account, the dissociation energy of the molecule PbO= 88.4=1.4 kcal/mole. The standard enthalpy at 25C of the reactions, Pb2O2(g) 2 PbO(g), Pb3O3(g) 3PbO(g), Pb4O4(g) 4 PbO(g), is 63.4=4, 126.4=6.0 and 202.0=10.0 kcal/mole respectively. (Author)