Abstrakt
Heat capacity and enthalpy increments of ternary strontium bismuth(III) oxides SrBi2O4 and Sr2Bi2O5 were measured by the relaxation time method (2-210K), DSC (253-352K) and drop calorimetry (570-1072 K). Temperature dependencies of the molar heat capacity in the form C-pm =161.97 + 45.936 x 10(-3) T - 1.7862 x 10(6)/T-2 J K-1 Mol(-1) and C-pm = 197.48 + 87.463 x 10(-3) T - 1.9282 x 10(6)/T-2 J K-1 mol(-1) for SrBi2O4 and Sr2Bi2O5, respectively, were derived by the least-squares method from the experimental data.
The molar entropies at 298.15 K, S degrees(m)(298.15 K) = 206.1 +/- 1.1 J K-1 mol(-1) for SrBi2O4 and S degrees(m),(298.15 K) = 261.2 +/- 1.4 J K-1 mol(-1) for Sr2Bi2O5, were evaluated from the low temperature heat capacity measurements.