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High Pressure Single Crystal Diffraction at PX^2
Published on: January 16, 2017
Cluster configurations in modulated EuVxMo8+/-yO14 crystals
1Laboratoire CRISMAT (UMR CNRS 6508), ISMRA, 14050 Caen CEDEX, France. h.leligny@crismat.ismra.fr
Acta Crystallographica. Section B, Structural Science
|August 6, 2000
Summary
Europium-vanadium-molybdenum oxide crystals exhibit one-dimensional incommensurate modulations and form novel metallic clusters. These structures reveal strong intercluster bonding within layers and between them.
Area of Science:
- Solid State Chemistry
- Crystallography
- Materials Science
Background:
- Orthorhombic crystals of the formula Eu(x)V(y)Mo(8+/-z)O(14) were studied.
- These crystals share similar lattice parameters and exhibit one-dimensional incommensurate modulations.
- Their structures are related to known lanthanum-molybdenum oxides but with key differences in modulation direction and symmetry.
Purpose of the Study:
- To investigate the crystallographic and structural properties of Eu(x)V(y)Mo(8+/-z)O(14) crystals.
- To characterize the nature of metallic clusters and intercluster bonding within these materials.
- To compare the structural features with related lanthanum-molybdenum oxide systems.
Main Methods:
- X-ray diffraction using Mo Kalpha radiation (lambda = 0.71073 Å).
- Analysis of crystal compositions and lattice parameters.
- Superspace group determination and modulation vector analysis.
Main Results:
- Three distinct compositions of Eu(x)V(y)Mo(8+/-z)O(14) were identified with varying gamma components.
- The crystals display one-dimensional incommensurate modulations along the c-axis with superspace group Cmca(00gamma)s00.
- Novel metallic clusters (e.g., Mo(9), Mo(10), Mo(6)V(4)) were discovered, alongside known types, with strong intercluster Mo-Mo, Mo-V, and V-V bonds (~2.6 Å).
Conclusions:
- The Eu-containing crystals possess centrosymmetric structures, contrasting with the polar structures of modulated La-containing analogs.
- The stacking of Mo/V atoms forms (001) layers of metallic clusters, with variations in cluster type and configuration along the c-axis.
- The study highlights the formation of significant intercluster bonding, contributing to the overall structural integrity and properties of these oxide materials.
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