Thermodynamics of the semiconductor–metal transition in the lanthanide monosulphides

Abstract

A simple principle of lanthanide thermochemistry is used to estimate the standard free energy change for the semiconductor–metal transition in the lanthanide monosulphides at 298.15 K. The results are in satisfactory agreement with the distribution of semiconducting and metallic monosulphides within the lanthanide series, and with the observed transition pressure regions in SmS, EuS, and YbS. In cases where experimental values of the standard enthalpies of formation are currently unavailable, estimated values for both semiconducting and metallic monosulphides are also obtained.