Vaporization thermodynamics of the ZnO–SnO2 system

• Composition of the vapor phase of the ZnO–SnO2 system is determined.
• Incongruent character of sublimation of Zn2SnO4 is stated.
• The partial pressures of the vapor species are measured.
• A p–x projection of the phase diagram is constructed.
• The standard enthalpy of formation of Zn2SnO4 is obtained.

Vaporization processes in the ZnO–SnO2 system have been studied by the Knudsen effusion technique in combination with mass spectrometric analysis of the vapor phase in the temperature range 1360 K to 1460 K. It has been identified by studying the ZnO–SnO2 system in quartz cells that its gas phase mainly consists of Zn(g), O2 and SnO(g).The partial pressures of the vapor species were determined at 1450 K. The incongruent character of the Zn2SnO4 vaporization was stated, and the p–x projection of the ZnO–SnO2 phase diagram at 1450 K was constructed. The standard molar enthalpy of formation of the mixed oxide Zn2SnO4 at 298 K was found to be −1296.2 ± 7.5 kJ · mol−1.