Analysis and Thermodynamics of the Vapor Phase over Liquid InTe at 1106 ± 2 K

Abstract

The vapor phase over normalInTefalse(1false) at 1106±2K was analyzed by an isothermal total exhaustion experiment with a Knudsen‐cell mass spectrometer. In+, In2+ , Te+, Te2+ , InTe+ , In2Te+ , InTe2+ , and In2Te2+ were observed. The appearance potentials of In+, In2+ , Te+, InTe+ , In2Te+ , InTe2+ , and In2Te2+ were 7.7, 9.6, 9.9, 8.6, 8.3, 8.2, and 7.6V, respectively, with an uncertainty of 0.3V. The fragment ions and their precursors were identified in three ways: (i) their appearance potentials were compared with those in the literature; (ii) the slopes of the plots of ionic intensities vs. time were compared; and (iii) all ions were assumed to be parents; hypothetical equilibrium constants for several vapor‐phase reactions involving the hypothesized gaseous precursors were checked for time‐dependent trends and, where possible, compared with literature data. From these three tests, we found that almost all of In+, In2+ , Te+, InTe+ , and In2Te+ came from In2normalTefalse(normalgfalse) , almost all of Te2+ came from Te2false(normalgfalse) , and almost all of InTe2+ and In2Te2+ came from In2Te2false(normalgfalse) . Thus, it was found that the vapor phase was composed of Te2false(normalgfalse) , In2normalTefalse(normalgfalse) , and In2Te2false(normalgfalse) . The mass spectrometer was calibrated with integrated ion intensities and the analysis of the fragmentation processes. Partial pressures of the vapor species were derived from ionic intensities. The equilibrium constant for the reaction2In2normalTe)(normalg+Te2)(normalg=2In2Te2)(normalgwas found to be false(1.81±0.10false)×10−3 Pa−1 . The standard enthalpy of the above reaction at 298 K was −310.9±0.5 normalkJ .