Thermodynamic properties of phases in the Yb-Bi-Se system

Abstract

The solid-state phase equilibria and thermodynamic properties of alloys in the Yb-Bi-Se system have been studied in the composition region YbSe-Bi2Se3-Se at temperatures from 300 to 400 K using emf measurements on concentration cells of the type $$ \left( - \right)YbSe\left( s \right)\left| {liquid electrolyte, Yb^{3 + } } \right|\left( {Yb - Bi - Se} \right)\left( s \right)\left( + \right). $$ The subsolidus phase diagram has been mapped out, and the partial thermodynamic functions of the YbSe pseudocomponent have been evaluated. Combining our data and the thermodynamic functions of YbSe and Bi2Se3, we have determined the partial thermodynamic functions of the ytterbium in the alloys and the integral thermodynamic functions of the ternary compounds YbBiSe3 (−ΔfG(298 K) = 496.0 ± 2.6 kJ/mol, −ΔfH(298 K) = 503.3 ± 4.3 kJ/mol, S0(298 K) = 214 ± 12 J/(mol K)), YbBi4Se7 (668.9 ± 8.7, 679.8 ± 9.0, 551 ± 14), and YbBi2Se4 (524.7 ± 4.6, 533.9 ± 5.7, 311 ± 11).