Thermodynamic Properties of the System Indium‐Oxygen

Abstract

The free‐energy change for the reaction 2In(l)+3NiO(s) = In2O3(s)+3Ni(s) was determined from 550° to 800°C from emf measurements on solid‐oxide galvanic cells. The results were used to develop an equation for the standard molar free energy of formation of In2O3, i.e. ΔG°ln2O3= ‐215,550+72.63T±450 cal/ mol. The standard molar enthalpy and entropy of formation of In2O3 at 298°K were calculated to be ‐214,000±1500 cal/mol and ‐69.03±o0.22 eu, respectively, using the available thermo‐chemical data. The absolute entropy of In2O3 at 298°K was calculated to be 32.23±0.22 eu. The free‐energy results of this study were used in conjunction with literature data to calculate partial pressures of the gaseous species over In2O3 for different experimental conditions. Copyright © 1972, Wiley Blackwell. All rights reserved