Conditions Extrêmes et Matériaux : Haute Température et Irradiation

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A.L.Rollet, M.Allix, E.Véron, M.Deschamps, V.Montouillout, M.R.Suchomel, E.Suard, M.Barre, M.Ocaña, A.Sadoc, F.Boucher, C.Bessada, D.Massiot, F.Fayon, 'Synthesis and structure resolution of RbLaF4', Inorg. Chem. 51 2272 (2012) doi:10.1021/ic202301e

The synthesis and the structure resolution of RbLaF4 are described. RbLaF4 is synthesized by the solid state reaction between RbF and LaF3 at 425°C under a non-oxidizing atmosphere. Its crystal structure has been resolved by combining neutron and synchrotron powder diffraction data refinements (Pnma, a = 6.46281(2) Å, b = 3.86498(1) Å, c = 16.17629(4) Å, Z=4). One dimensional 87Rb, 139La and 19F MAS NMR spectra have been recorded and are in agreement with the proposed structural model. Assignment of the 19F resonances is performed on the basis of both 19F-139La J-coupling multiplet patterns observed in a heteronuclear DQfiltered J-resolved spectrum and 19F-87Rb HMQC MAS experiments. DFT calculations of both the 19F isotropic chemical shieldings and the 87Rb, 139La electric field gradient tensors using the GIPAW and PAW methods implemented in the CASTEP code are in perfect agreement with the experimental values and support the proposed structural model. Finally, the conductivity of RbLaF4 and the luminescence properties of Eu-doped LaRbF4 are investigated.