Skip to Main content Skip to Navigation
Theses

Etude par RMN du solide multi-noyaux et modélisation des paramètres RMN de fluorures et d’oxyfluorures inorganiques

Abstract : This thesis focuses on the structural study of fluorides and oxyfluorides by combining solid state NMR, X-ray diffraction and PAW/GIPAW calculations of NMR parameters. The first part is devoted to the study of compounds of the KF-YF3 binary system. Linear correlation between experimental isotropic chemical shift (delta iso) and calculated isotropic shielding (sigma iso) values have been established, for 19F, 89Y and 39K, from assignments of NMR lines to crystallographic sites. These correlations lead to satisfactory agreements. In the case of 19F and 89Y, the link between NMR parameters and environment has been established. The calculated 39K NMR parameters allow satisfying reconstructions of the experimental complex spectra. The second part is dedicated to the study of the two ordered phases of LaOF. The optimizations and bond valence calculations showing that the atomic positions of F and O should be interchanged in both the phases, their structures have been refined. The agreement between experimental and calculated NMR parameters of 19F and 139La validates our structural models. Finally, the isotypic and disordered MO2F (M = Nb, Ta) compounds, since the O and F atoms occupy the same anionic site, have been studied. It is shown that the aqueous solution synthesis leads to hydroxylated and lacunary compounds, whose formulations have been determined by combining 19F NMR, XRD and TGA. The solid state synthesis enables to obtain pure compounds. DFT calculations were carried out on optimized 3 × 3 × 3 supercells that respect the partial order -M-O-M-O-M-F-. The good agreement between experimental and calculated NMR parameters of 19F validates the proposed model.
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-01822377
Contributor : Abes Star :  Contact
Submitted on : Monday, June 25, 2018 - 9:14:05 AM
Last modification on : Tuesday, March 31, 2020 - 3:23:01 PM
Long-term archiving on: : Wednesday, September 26, 2018 - 1:18:41 PM

File

2017LEMA1006.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01822377, version 1

Citation

Jamal Dabachi. Etude par RMN du solide multi-noyaux et modélisation des paramètres RMN de fluorures et d’oxyfluorures inorganiques. Matière Condensée [cond-mat]. Université du Maine, 2017. Français. ⟨NNT : 2017LEMA1006⟩. ⟨tel-01822377⟩

Share

Metrics

Record views

199

Files downloads

937