Premium
Phase relation and oxygen‐non‐stoichiometry of Perovskite‐like Compound SrCoO x (2.29 < x > 2.80)
Author(s) -
Takeda Y.,
Kanno R.,
Takada T.,
Yamamoto O.,
Takano M.,
Bando Y.
Publication year - 1986
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19865400929
Subject(s) - brownmillerite , perovskite (structure) , analytical chemistry (journal) , oxygen , stoichiometry , annealing (glass) , iodometry , materials science , strontium , phase (matter) , mineralogy , chemistry , crystallography , inorganic chemistry , metallurgy , organic chemistry , chromatography
Strontium cobaltates in the composition range, SrCoO 2.29 ‐SrCoO 2.80 , have been prepared under various conditions with respect to the oxygen pressure and temperature. Samples prepared at high temperatures (above 800°C) crystallized in the brownmillerite or perovskite type Structure Depending on oxygen Deficiency. A perovskite phase having large oxygen Deficiency, SrCoO 2.29 , and a brownmillerite solid solution, SrCoO x (2.42 < x < 2.52), were observed. On the other hand, samples annealed at low temperatures (below 800°C) did not crystallize in 2H type Structure with Sr:Co ratio of 1:1 but in the cobalt Deficient phase, 2H‐SrCo 1‐u O x (u ≈ 0.1) and Co 3 O 4 . The high oxygen content perovskite SrCoO 2.67‐2.80 was obtained by annealing the brown‐millerite phase under high oxygen pressures at 300°C. The electrical conductivity of SrCoO x (2.29 < x < 2.80) and the oxygen diffusion coefficient of the perovskite phase SrCoO x (x = 2.68, 2.75 and 2.80) were measured as a function of temperature. SrCoO 2.80 showed the very high diffusion coefficient of 2.3 × 10 −11 cm 2 sec −1 at 23°C.