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RESEARCH PRODUCT
Crystal structure of a new polytype in the V–P–O system: is ω-VOPO4 a dynamically stabilised metastable network?
J. AlamoAurelio BeltránDaniel Beltrán-porterPedro AmorósM. Dolores MarcosManuel Rocasubject
HydrogenThermal decompositionAb initiochemistry.chemical_elementGeneral ChemistryCrystal structureCondensed Matter PhysicsCrystallographyTetragonal crystal systemchemistryPhase (matter)MetastabilityGeneral Materials SciencePowder diffractiondescription
Abstract ω-VOPO 4 has been prepared by thermal decomposition of different oxovanadium hydrogen phosphates, namely VO(HPO 4 ) n H 2 O ( n =2( α ), 2(β) and 4) and β-NH 4 (VO 2 )(HPO 4 ). The ω-VOPO 4 phase only remains well crystallised at relatively high temperatures. Its crystal structure has been determined ab initio from X-ray powder diffraction data collected at 475°C. The cell is tetragonal (space group P4 2 /mmc) with a =4.8552(3) A and c =8.4301(6) A. Starting positional parameters were obtained by direct methods, and the structure was refined using Rietveld profile refinement principles. Disorder of two oxygen sublattices is observed. To rationalise some features of the crystal structure of this new phase, a dynamic model is proposed and discussed.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2001-08-01 | Journal of Physics and Chemistry of Solids |