Thermodynamic properties of yttrium cuprate
  The standard formation enthalpy and enthalpy from binary oxide of yttrium cuprate have been determined by solution calorimetry combining the solution enthalpies of Y2Cu2O5 and Y2O3 + 2CuO mixture in 6 M HCl at 323.15 K and literature data. The heat capacity of Y2Cu2O5 has been measured by adiabatic calorimetry from 8 up to 303 K. Smoothed values of heat capacities, entropies and enthalpies were calculated on the basis of experimental data. The thermodynamic functions (heat capacity, entropy and enthalpy) at 298.15 K have been calculated. On the basis of obtained data it has been obtained that above-mentioned complex oxide is thermodynamically unstable with respect to their decomposition into binary oxides at room temperatures. 
N.I. Matskevich, Yu.F. Minenkov, G.A. Berezovskii
cond-mat.mtrl-sci