Determination of Standard Gibbs Energy of Formation of Al₂Nd by Solution Calorimetry and Heat Capacity Measurement from Near Absolute Zero Kelvin

Abstract

The thermodynamic properties of Al₂Nd were investigated by calorimetry. The standard entropy of formation of Al₂Nd at 298 K, Δ_fS₂₉₈^o(Al₂Nd), was determined from measuring the heat capacities, C_p, from near absolute zero (2 K) to 300 K by the relaxation method. The standard enthalpy of formation of Al₂Nd at 298 K, Δ_fH₂₉₈^o(Al₂Nd), was determined by solution calorimetry in hydrochloric acid solution. The standard Gibbs energy of formation of Al₂Nd at 298 K, Δ_fG₂₉₈^o(Al₂Nd), was determined from these data. The results were obtained as follows: Δ_fS₂₉₈^o(Al₂Nd)/J·K⁻¹·mol⁻¹ = −10.7±1.2, Δ_fH₂₉₈^o(Al₂Nd)/kJ·mol⁻¹ = −105.03±27, and Δ_fG₂₉₈^o(Al₂Nd)/kJ·mol⁻¹ = −101.85±27.