The dielectric spectra corresponding to the static regime of dimethyl sulfoxide + water mixtures were recorded in the whole concentration range and in the temperature range from (253.15 to 333.15) K. For the mixtures rich in DMSO (0.60 < x DMSO ≤ 1, x = mole fraction) and rich in water (0 ≤ x DMSO < 0.1), it was possible to perform the investigations both in the liquid and solid phases of the samples. The determined melting temperatures were compared to the data available in the literature. The deviation from the additivity of the measured static permittivity of DMSO + water mixtures shows a maximum for x DMSO ≈ 0.35, indicating formation at that concentration of intermolecular entities (most probably they are 1DMSO·2H2O hydrogen-bonded complexes) of a relatively enhanced polarity.

The electrical conductivity was measured for dilute electrolyte solutions of lithium perchlorate (LiClO 4 ) in polyethylene glycols (PEG) of different molecular weights (200−600). The results were interpreted in the frame of the Stokes−Einstein−Nernst model. It was found (i) a breakdown of the model in the glycol-based polymeric matrices used and (ii) an increase of the deviation from the model predictions with increasing molecular weight of the matrix. The role of the flexibility of HO− [CH 2 −CH 2 −O] n −H chains in the efficiency of charge carriers transport in liquid glycols is discussed.

A novel inorganic‐organic hybrid compound, allylammonium hexabromobismuthate(III), (C3H5NH3)3BiBr6 (ABB), was synthesised and its structure determined by means of single‐crystal X‐ray diffraction studies at four temperatures (280, 230, 170 and 100 K). At 100 K, the compound crystallises in the monoclinic space group, C2/c. Its crystal structure consists of discrete BiBr63– anions and three inequivalent allylammonium (C3H5NH3)+ cations. Four solid‐solid structural phase transitions for ABB were detectable by means of DSC and dilatometric techniques: continuous (I↔II) at 272/272 K (upon heating/cooling), discontinuous (II↔III) at 218/215, discontinuous (III↔IV) at 205/204 K and discontinuous (IV↔V) at 146/144 K. The ferroelastic domain structure was observed over one intermediate phase (III) below 215 K. The electric properties of ABB have been measured over a wide temperature range (105–310 K). Low frequency relaxation processes with dielectric increments Δϵ1 ≈ 0.9 and Δϵ2 ≈ 0.05 were observed within phases II and V, respectively. Temperature‐dependent vibrational properties of ABB in the frequency region 3500–500 cm–1 and the molecular motions of its allylammonium cations were studied by means of proton magnetic resonance. The mechanisms of the phase transitions in the title compound are discussed.