Extending the family of oxygen ion conductors isostructural with La{sub 2}Mo{sub 2}O{sub 9}
- M.V. Lomonosov Moscow State University, Faculty of Physics, Leninskie gory 1, Moscow 119991 (Russian Federation)
X-ray diffraction characterization of materials prepared by solid-state reactions in the ternary systems La{sub 2}Mo{sub 2}O{sub 9}-Nd{sub 2}W{sub 2}O{sub 9}-'Nd{sub 2}Mo{sub 2}O{sub 9}{sup '} and La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}W{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} has shown that, in these systems, compounds isostructural with the oxygen ion conductor La{sub 2}Mo{sub 2}O{sub 9} exist in wide single-phase regions. Partial tungsten substitution for molybdenum may yield stable Ln{sub 2}Mo{sub 2-2x}W{sub 2x}O{sub 9} compounds with the La{sub 2}Mo{sub 2}O{sub 9} structure, where Ln is a rare-earth element different from lanthanum and praseodymium, e.g., neodymium. Tungsten also stabilizes Pr{sub 2}Mo{sub 2}O{sub 9}, which otherwise decomposes above 700 Degree-Sign C. A series of continuous solid solution was found in the La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} system. Polymorphism of compounds existing in the above ternary systems was studied by differential scanning calorimetry. The conductivity of most of the compounds studied approaches that of lanthanum molybdate. - Graphical abstract: La{sub 2}Mo{sub 2}O{sub 9}-Nd{sub 2}W{sub 2}O{sub 9}-''Nd{sub 2}Mo{sub 2}O{sub 9}'' and La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}W{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} phase diagrams. Single-phase regions of compounds with the La{sub 2}Mo{sub 2}O{sub 9} and Nd{sub 2}W{sub 2}O{sub 9} (Pr{sub 2}W{sub 2}O{sub 9}) structures are highlighted in blue and red. Highlights: Black-Right-Pointing-Pointer Phase formation in the La{sub 2}Mo{sub 2}O{sub 9}-Pr{sub 2}W{sub 2}O{sub 9}-Pr{sub 2}Mo{sub 2}O{sub 9} system has been studied. Black-Right-Pointing-Pointer Phase formation in the La{sub 2}Mo{sub 2}O{sub 9}-Nd{sub 2}W{sub 2}O{sub 9}-'Nd{sub 2}Mo{sub 2}O{sub 9}' system has been studied. Black-Right-Pointing-Pointer Compounds isostructural with La{sub 2}Mo{sub 2}O{sub 9} were found in wide single-phase regions. Black-Right-Pointing-Pointer Tungsten stabilizes Nd{sub 2}Mo{sub 2-2x}W{sub 2x}O{sub 9} compounds with the La{sub 2}Mo{sub 2}O{sub 9} structure. Black-Right-Pointing-Pointer The {alpha}{yields}{beta} phase transition of La{sub 2}Mo{sub 2}O{sub 9} is suppressed and the cubic phase is stabilized.
- OSTI ID:
- 22149909
- Journal Information:
- Journal of Solid State Chemistry, Vol. 196; Other Information: Copyright (c) 2012 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
Similar Records
Partial substitution of Mo{sup 6+} by S{sup 6+} in the fast oxide ion conductor La{sub 2}Mo{sub 2}O{sub 9}: Synthesis, structure and sulfur depletion
Synthesis and luminescence properties of the lithium-containing lanthanum-oxycarbonate-like borates