Compounds and subsolidus phase relations in the CaO-Co{sub 3}O{sub 4}-CuO system

Journal Article · Sat Oct 15 00:00:00 EDT 2005 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2005.06.042· OSTI ID:20721715

Miyazaki, Yuzuru ^[1]; Huang, Xiangyang ^[2]; Kajitani, Tsuyoshi ^[1]

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1. Department of Applied Physics, Graduate School of Engineering, Tohoku University, Aramaki Aoba 6-6-05, Aoba-ku, Sendai 980-8579 (Japan)
2. Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, 3-4-15 Nihonbashi, Chuo-ku, Tokyo 103-0027 (Japan)

We have investigated the subsolidus phase relations in the system CaO-Co{sub 3}O{sub 4}-CuO at 920 deg. C under 1atm of oxygen by means of powder X-ray diffraction method. Apart from the three known phases of Ca{sub 2}CuO{sub 3}, Ca{sub 3}Co{sub 2}O{sub 6} and (Co{sub 1-x}Cu{sub x}){sub 3}O{sub 4} spinel (0=<x=<0.06), two misfit-layered cobaltates have been identified. The first misfit is a solid solution, having a chemical formula [Ca{sub 2}(Co{sub 1-x}Cu{sub x})O{sub 3}]{sub p}CoO{sub 2} with 0=<x=<0.12, while the other misfit has a pinpoint composition of [Ca{sub 2}(Co{sub 0.65}Cu{sub 0.35}){sub 2}O{sub 4}]{sub p}CoO{sub 2}. Both the phases have an incommensurate b-axes ratio, p{approx}0.62, due to the size difference between the two subsystems. Another phase is found in the Cu-rich quasi-one-dimensional composite crystal Ca{sub p}(Cu{sub 1-x}Co{sub x})O{sub 2}(p{approx}0.83,0.08=<x=<0.34), but the terminal compound Ca{sub 0.83}CuO{sub 2} is not synthesized. The octahedral Co site in the Ca{sub 3}Co{sub 2}O{sub 6} phase can be partially substituted with Cu, up to 6%, to form the Ca{sub 3}(Co{sub 1-x}Cu{sub x}){sub 2}O{sub 6}(0=<x=<0.06) solid solution.

• OSTI ID: 20721715
• Journal Information: Journal of Solid State Chemistry, Vol. 178, Issue 10; Other Information: DOI: 10.1016/j.jssc.2005.06.042; PII: S0022-4596(05)00303-8; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALCIUM OXIDES
COBALT OXIDES
COPPER OXIDES
CRYSTAL STRUCTURE
CRYSTALS
OXYGEN
PHASE STUDIES
SOLID SOLUTIONS
SPINELS
X-RAY DIFFRACTION