Crystal structure of BaNaZr2F11: A phase recrystallizing from fluorozirconate glasses

International audienc

Crystal chemistry of anion-excess ReO3-related phases

International audienc

Characterization and Defect Structure of Anion-Excess Fluorite-Related Phases in LnOF–LnF3 Systems (Ln=Nd, Sm, Eu, Gd): From Isolated Defect Clustering to “Vernier” Modulated Phases

International audienc

ChemInform Abstract: High Resolution Powder Neutron Diffraction Study of the Tetragonal Anion-Excess Fluorite-Related LaF1.70O0.65 Phase.

International audienc

Cationic Distribution in α-MZr3F15 Series (M = Y, In, Ln, Tl)

International audienc

Short-range order and diffusion processes in the Na1-xBixF1+2x anion-excess solid solution

The F− diffusion processes within the anion-excess solid solution Na1−xBixF1+2x with fluorite-type structure have been studied by 19F-NMR investigation. Two types of fluoride ions, Fn and F′, are distinguished in the 19F-NMR spectra of rigid lattice at low temperature (T=175 K) and the distribution of fluoride ions among the two sites is determined by deconvolution of the experimental spectra. The short-range order in these materials is analogous to the clustering process observed in the K1−xBixF1+2x solid solution. It corresponds to an order between cubic entities and cubooctaedral clusters. Two diffusion mechanisms are identified on both sides of a Tr temperature. The first one at TTr to an F− exchange between cubic and cubooctaedral clusters

Effect of oxygen on short-range order in the Ba1-xBixF2+x solid solution

Various compositions within the range of the fluorite-type solid solution in the BaF2–BiF3–BiOl.5 system are investigated by impedance spectroscopy. This study is carried out along two lines of compositions: δ1, corresponding to the Bal−2z/3Bi2z/3F2+4z/3Oz solid solution, where z is the oxygen rate; and δ2, corresponding to the Bal−xBixF2+x−0.30O0.15 solid solution, where x is the bismuth rate. An approach to the nature of the fluorine–oxygen order is proposed which derives from the clustering process in the Bal−xBixF2+x fluoride solid solution

Fluorite-like phases in the BaF 2 -BiF 3 -Bi 2 O 3 system-synthesis, conductivity and defect clustering

Abstract A fluorite-like solid solution Ba 1 À x Bi x O z F 2 + x À 2z on the basis of cubic BaF 2 was synthesised in the BaF 2 -Bi 2 O 3 -BiF 3 system and the homogeneity range at 873 K was determined. The samples were studied by X-ray powder diffraction and electron diffraction, and their transport properties were measured by the complex impedance method at 300-623 K. Tendencies of variation of lattice parameters and transport properties were determined. These tendencies are discussed on the basis of a defect clustering hypothesis. Thermal treatment at 573 K of the solid solution, quenched from 873 K results in the formation of a new ordered tetragonal fluorite-like phase with lattice parameters a = 9.5355(4) Å , c = 18.151(1) Å .

Fluorite-like phases in the BaF2-BiF3-Bi2O3 system-synthesis, conductivity and defect clustering

A fluorite-like solid solution Ba1 − xBixOzF2 + x − 2z on the basis of cubic BaF2 was synthesised in the BaF2-Bi2O3-BiF3 system and the homogeneity range at 873 K was determined. The samples were studied by X-ray powder diffraction and electron diffraction, and their transport properties were measured by the complex impedance method at 300-623 K. Tendencies of variation of lattice parameters and transport properties were determined. These tendencies are discussed on the basis of a defect clustering hypothesis. Thermal treatment at 573 K of the solid solution, quenched from 873 K results in the formation of a new ordered tetragonal fluorite-like phase with lattice parameters a = 9.5355(4) Å, c = 18.151(1) Å