T 44 Thermodynamic and structural properties of PrBaCo2O5+delta [Text] / I. A. Leonidov, M. V. Patrakeev, E. B. Mitberg, O. N. Leonidova, V. L. Kozhevnikov // Inorganic Materials. - 2006. - Vol. 42, № 2. - P196-201 : il. - Библиогр. : с. 201 (4 назв.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ТЕРМОДИНАМИЧЕСКИЕ СВОЙСТВА -- КОБАЛЬТИТ ПРАЗЕОДИМА -- КАЛОРИМЕТРИЧЕСКИЕ ИССЛЕДОВАНИЯ -- ТИТРОВАНИЕ Аннотация: 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 Å, b = 11.932 Å, and c = 7.609 Å. The composition dependences of ΔH(O) and ΔS(O) indicate that the 3ap×3ap×2ap 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 2Co(3+)= Co(2+)+CoÓ4+ Полный текст |