Heat capacity and thermodynamic functions of Na2MoO4 in the temperature range 0–300 K

The heat capacities of two samples of Na2MoO4, prepared by different methods, were measured at low temperatures. Obtained image data differ significantly (from 3 to 7% at temperatures 50–300 K) from literature ones. Smoothed values of thermodynamic functions (heat capacity, entropy, change of enthalpy and Gibbs energy) were calculated in the temperature range 0–300 K. At temperature 298.15 K standard values are: image, S°(298.15 K) = 149.9 ± 0.2 J K−1 mol−1, H°(298.15 K) − H°(0 K) = 23.82 ± 0.02 kJ mol−1, Φ0(298.15 K) = 69.98 ± 0.24 J K−1 mol−1. Refined values of sodium molybdate entropy of formation and Gibbs energy of formation are: ΔfS°(Na2MoO4, 298.15 K) = −391.39 ± 0.60 J K−1 mol−1 and ΔfG°(Na2MoO4, 298.15 K) = −1351.0 ± 1.3 kJ mol−1, relatively.