Isobaric heat capacity and standard thermodynamic properties of cation-ordered layered perovskite-like oxides NaLnTiO(4) and A(2)Ln(2)Ti(3)O(10) (A = H, Na, K; Ln = La, Nd, Gd)

摘要

The heat capacities of protonated layered perovskite-like oxides H(1.64)K(0.36)Nd(2)Ti(3)O(10.)0.61 H2O and H(1.89)K(0.11)Nd(2)Ti(3)O(10.)0.60 H2O were measured by precision adiabatic vacuum calorimetry over the temperature range of (6-300) K. The standard thermodynamic functions: molar heat capacity, enthalpy, entropy, and the Gibbs energy of the compounds were evaluated from the experimental data of the heat capacities over the temperature range of T = (6-300) K. The deviation of experimental points from fitting curves obtained on the basis of Debye's theory. The overview on low-temperature heat capacity and standard thermodynamic properties of cation-ordered layered perovskite-like titanates NaLnTiO(4) and A(2)Ln(2)Ti(3)O(10) (A=H, Na, K; Ln=La, Nd, Gd) is present.