ENTHALPIES OF FORMATION OF UGA2 AND UGA3 BY CALORIMETRY

Enthalpies of formation of the intermetallic compounds, UGa2 and UGa3, at 298.15 K were determined by using high-temperature liquid gallium solution calorimetric measurements at 1427 K to be -40.4+/-6.0 and -38 .3+/-4.4 kJ gatom(-1), respectively. The enthalpies of formation of UG a2 at 1563 K and UGa3 at 1038 K were determined to be -79.1+/-2.5 and -40.6+/-1.5 kJ gatom(-1) by using the precipitation calorimetric metho d. The enthalpies of formation of UGa3 at 298.15 and at 1038 K are fou nd to be in agreement with each other, whereas that of UGa2 at 1563 K is highly exothermic compared to that at 298.15 K. (C) 1998 Elsevier S cience S.A.