Solid-state NMR study of mixed network sodium–niobium phosphate glasses
| Autor: | Laurent Delevoye, Jean-Paul Amoureux, Lionel Montagne, Jean-Jacques Videau, Gérard Palavit, Alexandrine Flambard |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Chemistry
Niobium Ionic bonding chemistry.chemical_element Condensed Matter Physics Dissociation (chemistry) Electronic Optical and Magnetic Materials Phosphate glass NMR spectra database Crystallography Solid-state nuclear magnetic resonance Chemical bond Octahedron Materials Chemistry Ceramics and Composites Nuclear chemistry |
| Zdroj: | Journal of Non-Crystalline Solids. :75-79 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/j.jnoncrysol.2004.07.046 |
| Popis: | x Nb 2 O 5 –(100 − x )NaPO 3 glasses with 0 ⩽ x ⩽ 40 were characterized by 31 P, 93 Nb and 17 O NMR. 31 P MAS-NMR indicates that Nb 2 O 5 depolymerises the sodium metaphosphate network with the formation of Q 1 and Q 0 sites. However, Nb 2 O 5 is only partially dissociated in NaPO 3 melt since the amount of Q n sites does not fit the calculated values for a total dissociation. 93 Nb NMR spectra show two niobium sites, assigned to corner and edge-shared NbO 6 octahedra. The quantity of corner-shared octahedra decreases when the quantity of Nb 2 O 5 increases in the glasses. An 17 O MQ-MAS spectrum was recorded at high magnetic field (18.8 T) on 17 O-enriched 6Nb 2 O 5 –94NaPO 3 glass. Considering the empirical correlation of quadrupolar constant to M–O bond ionicity, 17 O resonances were assigned to oxygen atoms in POP, PONa and PONb sites. No NbONb sites could be detected, because of their small quantity in the enriched sample. |
| Databáze: | OpenAIRE |
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