A. B. Slobodyuk

Ion mobility and transport in β-PbF2 doped with alkaline-earth fluorides

We have studied ion mobility and conduction in (1 − x)PbF2 · xMF2 (M = Mg2+, Ca2+, Sr2+, Ba2+; 0.05≤x≤0.1) solid solutions by 19F and 207Pb NMR and impedance spectroscopy. The results are used to analyze the factors governing the structure of the fluoride sublattice and the nature and energetics of ionic motion in the temperature range 170–550 K. The solid solutions are shown to have high ionic conductivity (∼10−4 to 10−3 S/cm at temperatures above 470 K, with activation energies Ea ≤ 0.3−0.6 eV) and are, therefore, potentially attractive for engineering materials with tailored electrical properties.

Ionic conduction in glasses in the MnNbOF5-BaF2-BiF3 system

The electrical conductivity of oxyfluoride glasses in the MnNbOF5-BaF2-BiF3 system in the temperature range 299–550 K was studied by impedance spectroscopy. It was shown that the conductivity is mainly caused by fluoride ions forming fluorobismuth polyhedra in the glass structure, being as high as 7.46 × 10−3 S/cm (533 K) in the 20MnNbOF5-30BaF2-50BiF3 system reaches, which is at the level of the best values for fluoride glasses.

Ionic mobility, ionic transport, and charge transfer mechanism in solid solutions (1 − x)PbF2-xMF n by the NMR and impedance spectroscopy data

The internal mobility and ionic conduction of solid solutions in systems PbF2-MF2 and PbF2-MF3 are studied by the NMR (19F, 27Al, 207Pb) and impedance spectroscopy methods. Factors that define the form of ionic movements and their energy characteristics in the temperature region 150 to 550 K are considered and analyzed. Temperature shifts of the frequency range that defines the ionic conduction of solid solutions are discovered on the basis of impedance spectroscopy data and explained. It is established that the high ionic conductance in lead difluoride doped with fluorides of metals of Groups II and III is caused by the diffusion of fluoride ions. The large values of specific conductance (10−4 to 10−3 S cm−1) at a relatively low activation energy (less than 0.6 eV) allow one to consider the solid solutions studied in the role of a basis for the obtaining of new fluoride materials with high ionic conductance.

Ionic Mobility in Glasses in the ZrF4-BiF3-MF Systems (M = Li, Na, K) as Probed by 7Li, 19F, and 23Na NMR

The ion mobility in new fluoride glasses (mol %) 45ZrF4 · 25BiF3 · 30MF (I) (M = Li, Na, K), (70 - x)ZrF4 · xBiF3 · 30LiF (II) (15 ≤ x ≤ 35), and 45ZrF4 · (55-x)BiF3 · xMF (III) (M = Li, Na; 10 ≤ x ≤ 30) has been studied by 7Li, 19F, and 23Na NMR in the temperature range 250–500 K. The character of ion motion in bismuth fluorozirconate glasses I and III is determined by temperature and the nature and concentration of an alkali-metal cation. Major type of ion mobility in glasses I–III at temperature 400–440 K are local motions of fluorine-containing moieties and diffusion of lithium ions (except for the glass with x = 10). The factors responsible for diffusion in the fluoride sublattice of glasses I have been determined. Sodium ions in glasses I and III are not involved in ion transport.

Ion conductivity of the plastic phase of the organic salt [(C4H9)4N]BF4

Based on the thermal and X-ray diffraction analysis, NMR spectroscopy, and ion conductivity data it was shown that the organic salt [n-Bu4N]BF4 has an orientationally disordered phase with a primitive cubic unit cell (space group

Ionic mobility and phase transitions in heptafluorodiantimonates MSb2F7 and Cs(1−x)Mx′Sb2F7 (M′ = K, NH4) according to NMR and DSC data

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Synthesis, Structure, Ion Mobility, Phase Transitions, and Ion Transport in Rubidium Ammonium Hexafluorozirconates

; unit cell parameter ac = 1.4886(2) nm) in the temperature range 62–161°C. The mobility of molecular fragments and anions increased during the phase transition, and the ion conductivity was relatively high, reaching ∼10−6 S/cm at 150°C.

Synthesis and complex study of potassium ammonium hexafluorozirconates: Ion mobility, phase transitions, and ionic conductivity in K2−n(NH4)nZrF6 compounds as probed by NMR, DTA, and impedance spectroscopy

A new zirconate with lithium and magnesium cations of composition Li2Mg(ZrF6)2 · 4H2O (I) has been synthesized and studied by different methods (X-ray crystallography, differential thermal analysis, IR spectroscopy, and NMR (1H, 7Li, 19F, including 19F MAS NMR). The framework structure of I is composed of edge- and vertex-sharing ZrF8 dodecahedra, Mg(Ow)2F4 octahedra, and Li(Ow)F4 square pyramids. The structure is additionally stabilized by O-H...F and O-H...O hydrogen bonds. Compound is dehydrated in one stage in the temperature range 105–200°C to form Li2Mg(ZrF6)2 (II). The latter undergoes irreversible phase transition at 365°C leading to its decomposition into a mixture of MgZrF6 (cubic) and Li2ZrF6 (hexagonal). According to IR and NMR data, the structure of fluorozirconate chains of compound I is retained after dehydration.