Standard enthalpies of formation of lanthanum gallides by high temperaturereaction calorimetry

The standard enthalpies of formation (Delta H-f(298.15)0) of La5Ga3, LaGa a nd LaGa2 at 298.15 were determined by high temperature liquid gallium solut ion calorimetry to be -62.6+/-4.5, -74.8+/-3.7 and -69.0+/-3.7 kJ gatom(-1) respectively. The enthalpy of formation of LaxGa1-x where. x=0.19 at 1125 K was determined by using precipitation calorimetry, to be -37.5+/-3.7 kJ g atom(-1). The partial enthalpy of solution of lanthanum in liquid gallium a t infinite dilution (Delta(H) over bar (infinity)(La)) at 1099 K was determ ined to be -167.9+/-6.8 kJ gatom(-1). (C) 2001 Elsevier Science B.V. All ri ghts reserved.