Defect structures in the brannerite-type vanadates. VIII. Synthesis of the Mg/sub 1-y/Li/sub y/V/sub 2-y/Mo/sub y/O/sub 6/ and Mg/sub 1-x-y/phi/sub x/Li/sub y/V/sub 2-2x-y/Mo/sub 2x + y/O/sub 6/ solid solutions: effect of strengthening the crystal lattice by substitution of monovalent ion for bivalent ion
It is shown that MgV/sub 2/O/sub 6/ and LiVMoO/sub 6/, both of the brannerite-type structure, exhibit miscibility in the entire composition range resulting in the formation of MgLi = Mg/sub 1-y/Li/sub y/V/sub 2-y/Mo/sub y/O/sub 6/ solid solutions. For y > 0.5 significant capacity of the MgLi matrix to the excess of Mo/sup 6 +/ cations compensated by cation vacancies phi appears and MgLiO = Mg/sub 1-x-y/O/sub x/Li/sub y/V/sub 2-2x-y/Mo/sub 2x+y/O/sub 6/ solutions become stable. Pronounced negative deviations from Vegard's law are simultaneously observed for MgLi solid solutions. An unusual phenomenon is thus observed; monovalent cation (Li/sup +/) substituted for bivalent cation (Mg/sup 2 +/) strengthens the brannerite-type lattice and increases its toleration to cation vacancies. A similar effect has recently been observed for ZnLi and ZnLiO solid solutions (K. Mocala and J. Ziolkowski, J. Solid State Chem. 71, 426 (1987)); the effect is absent, however, in the case of MnLi and MnLiO (J. Ziolkowski, K. Krupa, and K. Mocala, J. Solid State Chem. 48, 376 (1983)). Some speculations concerning this effect and some predictions are offered. X-ray data are listed for MgLi solid solutions of various compositions.
- Research Organization:
- Institute of Catalysis and Surface Chemistry, Krakow, Poland
- OSTI ID:
- 5649841
- Journal Information:
- J. Solid State Chem.; (United States), Vol. 71:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LITHIUM OXIDES
CRYSTAL STRUCTURE
PHASE STUDIES
MAGNESIUM OXIDES
MOLYBDENUM OXIDES
VANADIUM OXIDES
CATIONS
EXPERIMENTAL DATA
LATTICE PARAMETERS
SOLID SOLUTIONS
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
DATA
DIFFRACTION
DISPERSIONS
INFORMATION
IONS
LITHIUM COMPOUNDS
MAGNESIUM COMPOUNDS
MIXTURES
MOLYBDENUM COMPOUNDS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SCATTERING
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies