A study of the Composition of Tellurium Vapor by the Static Method

Abstract

The static method with the use of a zero-pressure gauge makes it possible to accurately measure the vapor pressure. The data on the temperature dependence of the unsaturated vapor pressure of the substance (in the absence of the condensed phase) in the static experiment allow determining the vapor’s composition. A multicomponent system consisting of molecules containing i number of atoms is considered. Mathematical methods are developed to study the molecular composition of a multicomponent vapor. In combination with the initial equations, a system of n linear equations with n unknowns is obtained. The system of equations is compatible and has a unique solution, since the determinant composed of the coefficients at the unknown partial pressures of the components is different from zero. The composition of tellurium vapor was studied experimentally by the static method. It is shown that tellurium vapor consists mainly of one-, two-, and four-atom molecules in equilibrium (Te2 = 2Te and Te4 = 2Te2). The processing of the experimental data made allows obtaining the equations of the temperature dependence of the constants and reveal the change in the average number of tellurium atoms in the gas phase in a broad range of pressures and temperatures.