Uranium chalcogenides--III : Heat capacities and thermodynamic properties of US1[middle dot]9 and USe2 from 5 to 350[deg]K

Abstract

Heat capacities have been measured and derived thermodynamic properties calculated for the structurally related US1[middle dot]9 and USe2 phases from 5 to 350[deg]K. Values of the heat capacity (Cp), entropy (S[deg] - S[deg]0) and Gibbs energy function [-(G[deg] - H[deg]0/T] at 298[middle dot]15[deg]K in cal mol-1 [deg]K-1 are 17[middle dot]68, 25[middle dot]91 and 13[middle dot]82 for US1[middle dot]9 and 18[middle dot]92, 31[middle dot]98 and 17[middle dot]86 for USe2, respectively. Schottky-type anomalies are present in US1[middle dot]9; a [lambda]-type thermal anomaly with [Delta]St = 0[middle dot]19 cal mole-1 [deg]K-1 occurs at 13[middle dot]1 [deg]K in USe2.