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The thermodynamic properties of Al 2 Nd were investigated by calorimetry. The standard entropy of formation of Al 2 Nd at 298 K, Á f S o 298 (Al 2 Nd), was determined from measuring the heat capacities, C p , from near absolute zero (2 K) to 300 K by the relaxation method.

To provide for the future progression of the theoretical calculations beyond the adiabatic approximation by taking account of not only the electronic wave functions but also the nuclear wave functions, the formation energy, ⌬ f E total , determined experimentally from the ground state to the thermally excited state is inevitably necessary. In the present study, for each intermetallic compounds of the Mg-Zn and Mg-La binary systems, the standard enthalpy of formation, ⌬ f H T o , which is defined as the sum of ⌬ f E total and the volume work, p⌬ f V, was determined from 2 K to high temperature by combining solution calorimetry with heat capacity measurement.Because the p⌬ f V term for solids is negligibly small, the ⌬ f E total values at T are approximately equal to the measured ⌬ f H T o values. Thus the ⌬ f E total values obtained extrapolated to 0 K from the data measured near 2 K were consistent with ones obtained by the ab initio FLAPW energetic calculation. Temperature dependences of the ⌬ f E total values were small below 20 K. However, the ⌬ f E total values over 20 K decreased linearly as a function of temperature due to the enhanced lattice vibration. In the near future, the ⌬ f E total values obtained in the present study will be used for constructing the Correspondence to: M. Morishita;

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Relative partial molar Gibbs energies of the Mg component substituted into the Zn site, Á " G G ). When the symmetric atomic configuration at the stoichiometric composition was violated by antisite substitution, the relative partial molar thermodynamic value of lattice defect was found to be very large.