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The salt quinolinium tetrabromothallate(III) is orthorhombic Pna21 with the following unit cell dimensions: a = 9.582(2), b = 10.0210(19), c = 14.916(2) Å, Z = 4. The structure was solved by Patterson methods and refined to a final R-value of 0.0452 for 2043 observed reflections. The examination of the structure shows quinolinium cations separating chains of tetrahedral [image omitted], these chains are perpendicular to the c axis. Infrared spectra confirms the presence of the organic cations, differential scanning calorimetry reveals a transition at T = 406 K. Electrical measurements and X-ray powder diffraction were performed to discuss the mechanism of the phase transition. [ABSTRACT FROM AUTHOR]

Penthylene diammonium pentachlorothallate(III) exhibits a phase transition at 316 K This transition has been characterized by optical birefringence, dielectric measurements differential scanning calorimetry and spectroscopic measurements on polycrystalline samples. The space group and the cell parameters of phase I were determined by X-ray diffraction from single crystals. Phase I has space group P2 1 2 1 2 1 , with Z = 4, a = 7.696(3), b = 13.2890(17) and c = 13.503(18) Å. The transition is both displacive and order-disorder involving mainly conformational changes of the organic chain [NH 3 (CH 2 ) 5 NH 3 ] 2+ coupled with distortion of the TlCl 6 octahedra. This behaviour and the crystal dynamics will be discussed and compared with those found in the literature for homologous compounds. [ABSTRACT FROM AUTHOR]

The electric conductivity of the [C 6 H 18 N 2 ] SbCl 5 [C 6 H 18 N 2 ] Cl 2 crystals (abbreviated as DEDA) has been studied by means of impedance analysis in a high temperature regime. The results have been correlated with ones obtained by means of CW 1 H NMR analysis and the crystal structure of [C 6 H 18 N 2 ] SbCl 5 [C 6 H 18 N 2 ] Cl 2 . It was found that conductivity increases at the temperature which corresponds to the onset of pseudo-C 3 reorientational motion of the N,N-diethylethylenediammonium cation. The cations reorientations are accompanied by a chemical exchange and proton diffusion in the hydrogen bridge bonds. These results have shown that below 393 K the conduction of the crystals studied is a cooperative process involving both molecular motions prior to the proton exchange and migration along the hydrogen bonded chain (the Grotthus type diffusion mechanism of proton transport). The microscopic model of conductivity as well as the proton transfer path is proposed. [ABSTRACT FROM AUTHOR]