Growth and microhardness studies on NH4Sb3F10 single crystals

Methods of 19F NMR and impedance spectroscopy are used to investigate the internal mobility of fluoride (ammonium) ions and electrophysical characteristics of complex trivalent antimony fluorides MSb4F13, MSb3F10, MSb2F7, M2Sb3F11, M3Sb4F15, and MSbF4 (M is an alkali cation, ammonium, thallium). The ion motion types in the cationic and anionic sublattices of the fluorides are determined at 150–500 K. The polymorphous transformations in the fluorides are usually phase transitions to a superionic state and their high ionic (superionic) conductivity (σ ≥ 10−4 to 10−2 S cm−1 at 400 K) is due to the diffusion motion of ions of fluoride, ammonium, and possibly sodium, potassium, and thallium. The high polarizability of thallium ions favors the development of high mobility of fluoride ions in the fluorides.

Superionic Conduction in Complex Fluorides of Antimony(III) MnSbxFy (M—Cations of an Alkali Metal, Ammonium, or Thallium, n = 1–3, and x = 1–4)

Growth and microhardness studies on NH4Sb2F7 single crystals

Growth, structural, optical, and photo conductivity studies of potassium tetra fluoro antimonate crystal

Ion mobility, conductivity, structure, and phase transitions in K0.7M0.3SbF4 compounds with M=Rb, NH4

19F NMR spectra and relaxation times T,1, T2, T1e and electric conductivity in isostructural polycrystalline pentafluoroantimonates (III) M2SbF5 (M = Rb, K, Cs, Tl, NH4) are measured. It is found that the observed changes in the NMR spectra and relaxation times with temperature are determined by three types of motion: anisotropic and isotropic reorientations of [SbF5E]2− octahedra and diffusion motion of the fluorine ions. Parameters of these motions are found. All the compounds investigated show high conductivity at high temperature, amounting in the case of thallium and ammonium salts the values of σ = 101 to 100Ω−1 m−1 typical of superionic crystals. It is shown that the observed high conductivity is determined by fast diffusion motion of fluorine ions. On the basis of the data obtained a mechanism of fluorine ion diffusion is proposed. In (NH4)2SbF5 at 398 K a phase transition is found.



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NMR Study of Internal Motions in a New Family of Ionic Conductors M2SbF5

The 19F nuclear spin-lattice relaxation times and NMR spectra have been measured in polycrystalline alkali hexafluosilicates. The effect of the pressure on the SiF6 group motion is studied and discussed.

B. I. Cherkasov

Papers

NMR Study of Internal Motions in a New Family of Ionic Conductors M2SbF5

Internal Motion in Hexafluosilicates of Alkali Metals at High Hydrostatic Pressure

NMR study of sodium and lithium hexafluorosilicates