Thermodynamic Properties of the Chalcogenide Phases in the Bi-Te-S System

The Bi-S-Te system has been studied using emf measurements in the composition region Bi2S3-Bi2Te3-Te-S at temperatures in the range 300-450 K. We have calculated relative partial molar functions of bismuth in alloys and used the results to obtain self-consistent sets of the standard Gibbs free energy, standard enthalpy, and standard entropy of the Bi2S3, Bi2Te3, and Bi2Te2S compounds and a solid solution with the composition Bi2Te1.8S1.2, based on the last compound. The data obtained for Bi2S3 and Bi2Te3 have been compared to data available in the literature. The thermodynamic functions of Bi2Te2S and Bi2Te1.8S1.2 have been determined for the first time.

Automated summary

The Bi-S-Te system was studied in the composition region of Bi2S3-Bi2Te3-Te-S through emf measurements at temperatures ranging from 300 to 450 K. The thermodynamic properties of the compounds Bi2S3, Bi2Te3, Bi2Te2S, and Bi2Te1.8S1.2 were calculated, with comparisons made to existing literature data for Bi2S3 and Bi2Te3. New thermodynamic data for Bi2Te2S and Bi2Te1.8S1.2 were determined for the first time.