Study of the vaporization of solid AlAs

The vaporization of solid AlAs was studied using the mass spectrometry and Knudsen effusion techniques. This compound vaporizes according to the reaction View the MathML source The pressure of As2(g) depends on the temperature according to the equation View the MathML source where P is in kilopascals. A value of ?H298° = 163 ± 7 kJ mol-1 associated with the vaporization reaction was derived by second-law treatment of the pressure data. The free-energy function and the standard heat of formation (?Hform° = 62 ± 7 kJ mol-1) of AlAs(s) were also calculated.