Incongruent effusion of ZnGa8S13(s)

Article abstract of DOI:10.1016/0022-5088(89)90432-3

The chemistry and thermodynamics of vaporization in a Knudsen effusion cell of the phase ZnGa₈S₁₃ was studied in the range 1115 - 1246 K where the vapor pressure ranged from 0.25 to 10.0 Pa. Samples prepared by sealed-tube methods and characterized by X-ray diffraction were studied by the simultaneous Knudsen and torsion (Volmer) effusion method. ZnGa₈S₁₃(s) effused incongruently in equilibrium with a saturated solid solution (sss) of ZnS in Ga₂S₃, Ga₂S(g), Zn(g), and S₂(g), always on the ZnS-Ga₂S₃ join. Ga₂S₃(sss) then effused with net loss of ZnS to the vapor until the composition of Ga₂S₃ was reached. Vapor analysis by combining measured rates of mass loss and momentum loss allowed analysis of the vapor and calculation of equilibrium constants of the effusion equations.