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The electrical conductivity (σ) of Ca1–xPrxMnO3–δ (х = 0–0.15) manganites with a perovskite-like structure has been measured by the four probe method in air at temperatures (T) from 320 to 1220 K. The results have been analyzed in terms of a model of small adiabatic polarons. The observed decrease in σ with increasing T is primarily due to the decrease in carrier concentration as a result of Mn3+ disproportionation into Mn2+ and Mn4+. The polaron mobility ranges from 0.2 to 1.2 cm2/(V s) and decreases with increasing praseodymium content.

The Seebeck coefficient (S) of Ca1–x Pr x MnO3–δ (х = 0, 0.05, 0.10, 0.15) manganites with a perovskite-like structure has been measured in air at temperatures (T) from 300 to 1200 K. The negative sign of their S indicates that all of the samples have n-type conductivity. The observed increase in the magnitude of the Seebeck coefficient with increasing T is interpreted in terms of small-polaron transport with allowance for the decrease in Mn3+ concentration as a result of the disproportionation reaction 2Mn3+ = Mn2+ + Mn4+. Based on a theoretical analysis of experimental S(T) data, we calculated equilibrium constants for the disproportionation reaction, carrier concentration, and the concentration of sites available for carrier migration as functions of temperature. It has been shown that, for an adequate analysis of electron hopping and calculation of the Seebeck coefficient of the electron-doped manganites, the spin state of the Mn4+ ions should be taken into account.

The oxygen content of the double cobaltite PrBaCo2O5 + δ was determined by coulometric titration in broad temperature and oxygen pressure ranges, and the partial thermodynamic functions of oxygen were evaluated. The results on the nonstoichiometry and structural properties of PrBaCo2O5 + δ demonstrate that, at 5 + δ < 5.3, this cobaltite has a high-temperature phase with lattice parameters a = 11.774 A, b = 11.932 A, and c = 7.609 A. The composition dependences of $$\Delta \bar H(O)$$ and $$\Delta \bar S(O)$$ indicate that the 3a p × 3a p × 2a p orthorhombic structure persists in the range 5.15 ≤ 5 + δ ≤ 5.30. Some of the Co3+ ions are shown to disproportionate according to the scheme 2Co3+=Co2++Co4+.

The equilibrium oxygen content of YBa2Cu3-xCoxO6+δ (0.2 ≤x ≤ 0.8) solid solutions was determined by coulometric titration at temperatures in the range 600–850°C and oxygen pressures 1 ≤po 2 ≤ 105 Pa. The partial enthalpy and entropy of oxygen dissolution were evaluated as a function of composition. The thermodynamic functions were found to change sharply near the high- and low-oxygen limits of the solid solution. The results are interpreted in terms of a quasi-chemical model considering three inequivalent oxygen sites in the basal plane.