Thermochemistry and High Temperature Thermodynamic Properties of Rare Earth-Alkaline Earth-Copper Oxide Superconductors

1987 ◽  
Vol 99 ◽  
Author(s):  
Lester R. Morss ◽  
David C. Sonnenberger ◽  
R. J. Thorn
Keyword(s):  
Alkaline Earth ◽  
Enthalpy Of Solution ◽  
Solution Calorimetry ◽  
Molar Enthalpy ◽  
Enthalpies Of Formation ◽  
Oxide Superconductors ◽  
Vapor Pressures ◽  
Free Energies ◽  
Perchloric Acid Solution ◽  
Copper Oxide Superconductors

ABSTRACTEnthalpies of formation of the perovskite-related oxides, La1.85 Sr0.15CuO4, YBa2Cu3Oy, with y = 6.93, 6.69, and 6.47 have been determined at 298.15 K by perchloric acid solution calorimetry. Enthalpies of formation and free energies of reactions with H2 O(g) and CO2 (g) have been evaluated. The partial molar enthalpy of solution of oxygen in YBa2 Cu3Oy has been determined and compared with values derived from measurements or the equilibrium partial vapor pressures of oxygen. The significance of the defect state thermochemistry in conductivity is identified.

Thermodynamic properties of multicomponent electrolyte solutions in mixed solvents. 5• HCl + NaCl + urea + water at 278.5–318.15 K

1988 ◽  
Vol 66 (4) ◽  
pp. 637-644 ◽  
Author(s):  
Dian-Yuan Men ◽  
Jia-Zhen Yang ◽  
Chun-Yu Liang ◽  
Li-Tian Zhang ◽  
Huan Gao ◽  
...  
Keyword(s):  
Mixed Solvents ◽  
Electrolyte Solutions ◽  
Absolute Temperature ◽  
Molar Enthalpy ◽  
Free Energies ◽  
Force Measurements ◽  
Solution Theory ◽  
Electrolytic Solution ◽  
Harned's Rule ◽  
Electromotive Force Measurements

This paper reports electromotive force measurements of the cells[Formula: see text]and[Formula: see text]in mixed solvents of urea, mole fraction x = 0.05, at five temperatures from 278.15 to 318.15 K. The standard potentials of Ag–AgCl electrode in mixed solvents were obtained from the emf of cell (A) for HCl of molality mA from 0.02 to 0.11 mol kg−1, both by extrapolation on the basis of an extended Debye–Hückel equation and by a polynomial approach proposed in this paper on the basis of Pitzer's electrolytic solution theory. The standard free energies of transfer for HCl are discussed. The activity coefficients of HClγA in HCl + NaCl + urea + water have also been obtained from the emf of cell (B) at constant total ionic strength I = 0.5, 1.0, 1.5, and 2.0 mol kg−1. The experimental results show that HCl obeys Harned's rule and log γA is a linear function of absolute temperature T. They also indicate that the relative partial molar enthalpy of HCl obeys a similar Harned's rule.

Correlation in Metallic Copper Oxide Superconductors: How Large is it?

1990 ◽  
pp. 463-473
Author(s):  
W. E. Pickett ◽  
H. Krakauer ◽  
R. E. Cohen ◽  
D. Singh ◽  
D. A. Papaconstantopoulos
Keyword(s):  
Copper Oxide ◽  
Metallic Copper ◽  
Oxide Superconductors ◽  
Copper Oxide Superconductors
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