Thermodynamic investigation of gaseous yttrium germanides and silicides.

The equilibria involving the gaseous species above the Y–Ge and Y–Si alloy systems have been experimentally investigated by the high temperature mass spectrometer technique. The gaseous molecules YGe, YSi, and YSi2 were identified and their partial pressures were measured as a function of temperature. The experimentally determined reaction enthalpies were combined with appropriate literature data to obtain the following atomization energies, ΔH○a,0 and standard heats of formation, ΔH○f,298 , in kJ mol-1: YGe, 275.4 ± 11.4 and 522.4 ± 11.4; YSi, 253.8 ± 17.3 and 625.3 ± 17.3; YSi2, 800 ± 21 and 528 ± 21. [ABSTRACT FROM AUTHOR]