A remarkable feature of organic salts is easy reorientation of organic groups, especially in high-temperature phases. It would be expected that the reorientational motion of organic groups promotes also ion transport processes within the crystal structure. In this work thermal and transport properties of solid organic salt (n-C4H9)4NI were investigated by methods of DSC, dilatometry, conductivity measurements and NMR spectroscopy. It was proposed that three low-temperature phases, II, III and IV, along to the high-temperature phase I appear in this salt after heat treatment. The conductivity and temperature stability range of the low-temperature phases depend on conditions of the heat treatment of the salt. Temperature intervals of stability of phases II and III considerably increases after prolonged heating in the melt. In parallel, the conductivity of all low-temperature phases increases in contrast to the conductivity of the phase I. These facts may be explained by the formation of extrinsic iodine vacancies as a result of the dissolution of tributylanine formed at partial thermal decomposition of the salt. According to 1H NMR data, in high-temperature phase TBA cations are mobile. No information on anionic diffusion in this phase was obtained due to a low intensity of 127I NMR spectra. The most mobile defects in low-temperature phases of (n-C4H9)4NI seem to be iodine vacancies.

Composite solid electrolytes were synthesized from the organic salt dimethylammonium chloride (1–x)C2H8NCl–xAl2O3. Their physicochemical properties were studied. In the starting C2H8NCl salt, there is a phase transition at 39°C accompanied by an increase in conductivity by two orders of magnitude. The conductivity of the high-temperature phase is 9.3 × 10–6 S/cm at 160°C. A differential scanning calorimetry study showed that the salt in the composites spreads over the oxide surface and at x > 0.6 the salt melting enthalpy decreases to zero. The conductivity of the resulting composites was studied by impedance spectroscopy. It was shown that heterogeneous doping leads to a sharp increase in ion conductivity to 7.0 × 10–3 S/cm at 160°C and a decrease in the activation energy to 0.55 eV.

The ion conductivity of the salts [(C4H9)4N]BF4 and [(C4H9)4N]Br was studied in vacuum at temperatures from room temperature to 190 and 135°C, respectively. The salts have phase transitions to disordered high-temperature phases accompanied by an increase in conductivity. [(C4H9)4N]Br has higher conductivity than [(C4H9)4N]BF4. As the conductivity decreases with the increasing size of the anion, the BF4 – and Br– anions are the most probable current carriers in the salts.

Data on studies of the phase composition, thermal and transport properties of cesium nitrite are presented. Transport properties of the salt, including a sample doped by barium cations, are studied in detail. Values of enthalpies of defect formation and migration are estimated. The Hebb-Wagner method was used to evaluate the contribution of electron-hole conductivity. It is shown that conductivity is ionic and charge carriers are cesium ions migrating over cation vacancies.

См/см при 150°C. 3n; параметр ячейки ас = 1.4886(2) нм). При фазовом переходе увеличивается подвижность молекулярных фрагментов и анионов, при этом наблюдается относительно высокая ионная проводмость, достигающая 10-6 См/см при 150°C.

The conductivity of rubidium nitrate doped with barium nitrate in studied aimed at inserting cationic vacancies into the rubidium nitrate lattice. The conductivity of the RbNO3-II phase is shown to increase in proportion with the dopant concentration, which points to the formation of solid solutions and the increase in the concentration of cationic vacancies. The solubility of barium nitrate in phases RbNO3-III and IV is low; hence, the conductivity of these phases is virtually independent of the dopant content. The insignificant increase in conductivity of phase IV in the sample containing the high concentration of barium nitrate (1 mol %) is probably associated with the effect of the heterogeneous Ba(NO3)(2).

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 \(P\bar 43n\); unit cell parameter a c = 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.

The properties of orientationally disordered phases (ODPs) and primarily systems based on alkali metal perchlorates and nitrates studied earlier are reviewed. The crystal-chemical effects (cation and anion size, conduction channel, and free volume of the crystal lattice) on the conductivity of alkali metal perchlorates were analyzed. Computer simulation of rubidium nitrate was performed by the classical molecular dynamics method.

Results of studying the dependence of conductivity of molten magnesium chloride on the electric field intensity are presented. Limiting conductivities of the MgCl2 melt are obtained that exceed the ordinary values by 265 and 253% at 1000 and 1040 K.

A short review of transport properties of orientationally disordered phases (ODP) of alkali nitrates and perchlorates is presented. Analysis of the data shows that the conductivity, the activation energy and the pre-exponential factor do not change trivially with the increase of the cation size. It may be explained by two mechanisms: a classic one and a cooperative mechanism involving reorientation of anions, the latter becomes dominant in systems with a large free volume. Among nitrates ODP RbNO3-III is the most conducting and its stability range may be controlled via cationic and anionic substitutions. The mechanism of the ionic transport in RbNO3 seems to be different from those in perchlorates. According to the results of MD simulation conductivity is limited by the defect formation rather than the cation migration which proceeds via vacancy mechanism. Correlation times for the anion reorientation process correlate with ionic conductivity values thus suggesting that the cation diffusion and anion reorientation are closely interrelated.

Conductivity and thermodynamic properties of solid solutions (1−x)RbNO3–xRbNO2 were investigated over entire concentration range of 0<x<1. As shown by differential thermal analysis and conductivity measurements, the introduction of a small concentration of nitrite into rubidium nitrate leads to an decrease in the temperature of phase transitions IV↔III and III↔II, so that highly conducting phase III becomes stable at low temperatures. The introduction of smaller NO2− anions results in the increase in the conductivity of the RbNO3-III phase, the activation energy and a pre-exponential factor of conductivity decrease with the doping and III–IV transition becomes diffusive. A possible reason of these effects is a strong influence of nitrite ions to the orientational disorder of the anionic sublattice of RbNO3.

The dependence of conductivity of copper (I) halides (CuCl, CuBr, and CuI) and their melts on the electric field strength is studied. Conductivity of superconducting phases and their melts reaches limiting high-voltage values exceeding the usual values by up to 100% even at ∼0.5 MV/m.

The dependence of conductivity on the electric field intensity (EFI) is studied for silver iodide in α-phase and in the molten state. The conductivity of a solid superionic and its melt increases at the EFI increase and tends to limiting values in the field of the order of MV/m.