Standard enthalpies of formation of Me 5Ge 3( Me ≡ Sc, Y, La) by high-temperature calorimetry

Abstract

The standard enthalpies of formation of the germanides Me 5Ge 3( Me ≡ Sc, Y, La) were determined by high-temperature calorimetry at 1473 ± 2 K. The following values are reported: ΔH f o ( Sc 5 Ge 3) = − 747.3 ± 30.8 kJ mol − 1 and ΔH f o ( Y 5 Ge 3) = − 718.2 ± 39.9 kJ mol − 1, measured by solute-solvent drop calorimetry, and ΔH o f ( La 5 Ge 3) = − 543.9 ± 8.0 kJ mol − 1, measured by the direct synthesis method. The results are compared with estimated values from Miedema's semi-empirical model.