Search

Sodium cadmium orthophosphate NaCdPO was prepared by solid-state reaction method at high temperature under air atmosphere. Structural, morphology and electrical properties have been investigated. X-ray powder diffraction analysis indicated that the sample is well crystallized in the orthorhombic maricite structure with Pmnb space group. The composition and morphology of the compound were performed by energy dispersive spectroscopy coupled with scanning electron microscope. Electrical properties were carried out in the frequency range 209 Hz-1 MHz at various temperatures 595-700 K using impedance spectroscopy technique. Nyquist plots analysis revealed the presence of two contributions at different temperatures associated with grain and grain boundary. In order to explain the impedance results an equivalent circuit has been proposed. The AC conductivity was analyzed by Jonscher's power law of frequency ( σ ( ω) ∞ Aω ). At high frequency, the conduction mechanism was well interpreted in term overlapping large polaron tunneling. [ABSTRACT FROM AUTHOR]

The complex impedance of the Ag2ZnP2O7 compound has been investigated in the temperature range 419–557 K and in the frequency range 200 Hz–5 MHz. The Z′ and Z′ versus frequency plots are well fitted to an equivalent circuit model. Dielectric data were analyzed using complex electrical modulus M* for the sample at various temperatures. The modulus plot can be characterized by full width at half-height or in terms of a non-exponential decay function $$ \phi \left( {\text{t}} \right) = \exp {\left( { - {\text{t}}/\tau } \right)^\beta } $$. The frequency dependence of the conductivity is interpreted in terms of Jonscher’s law: $$ \sigma \left( \omega \right) = {\sigma_{\text{dc}}} + {\text{A}}{\omega^n} $$. The conductivity σdc follows the Arrhenius relation. The near value of activation energies obtained from the analysis of M″, conductivity data, and equivalent circuit confirms that the transport is through ion hopping mechanism dominated by the motion of the Ag+ ions in the structure of the investigated material. [ABSTRACT FROM AUTHOR]

The temperature dependence of the electrical conductivity of the compound 2,4,4-trimethyl-4,5-dihydro-3 H-benzo[b] [1,4] diazepin-1-ium tetrachlorocadmiate in the different phases follows the Arrhenius law. The imaginary part of the permittivity constant is analyzed with the Cole–Cole formalism. In the temperature range 348–394 K, the activation energy of conductivity obtained from complex permittivity in regions I and II are, respectively, 1.03 and 0.33 eV, and Em (in regions I and II are, respectively, 0.97 and 0.36 eV) obtained from the modulus spectra is close, suggesting that the ion transport is probably due to a hopping mechanism. The Kohlrausch–Williams–Watts function, $$ \varphi (t) = \exp \left( { - {{\left( {\frac{t}{{{\tau_{\text{KWW}}}}}} \right)}^\beta }} \right) $$, and the coupling model are utilized for analyzing electric modulus at various temperatures. The decreasing of β at 373 K is due to approaching the temperatures of change in the conduction mechanism of the sample. [ABSTRACT FROM AUTHOR]

Highlights: [•] The [N(C3H7)4]2SnCl6 compound has been synthesized in a molar ratio 2:1. [•] Spectroscopic properties of TPACl ligand and [N(C3H7)4]2SnCl6 compound were studied. [•] The optimized molecular geometry of [N(C3H7)4]2SnCl6 compound was investigated. [•] Vibrational wavenumbers calculations based on DFT were reported and discussed. [•] The FT-IR spectra of TPACl ligand and its complex [N(C3H7)4]2SnCl6 were compared. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis, X-ray powder and Raman description are reported for [N(CH3)4]2CoCl2Br2 compound. The calorimetric study shows three endothermic peaks at 289K, 323K and 408K. The compound crystallizes in the orthorhombic system, space group Pnma with a =12.384Å, b =9.058Å and c =15.647Å. The dielectric spectra were measured in the frequency range 10−1–106 Hz and temperature interval from 200 to 305K. The dielectric permittivity shows that this compound exhibits a ferroelectric–paraelectric phase transition at 290K. The frequency dependent permittivity is interpreted in the non-Debye model. The temperature dependence of the low frequency limit of the bulk AC conductivity σdc is well described by the Arrhenius equation: σdc = σ 0 exp(−Ea /kT). [Copyright &y& Elsevier]

Abstract: Synthesis, crystal structure, 13C CP-MAS-NMR analysis and impedance spectroscopy study are reported for a new organic–inorganic hybrid salt, [C7H12N2][ZnCl4], consisting of one 2,4-diammonium toluene cation and one [ZnCl4]2− anion. The Zn atom is in a slightly distorted tetrahedra coordination environment. The structure can be described by the alternation of ionic and organic layers. The cohesion of the material is assured by strong charge-assisted N–H⋯Cl interactions established between ammonium groups and discrete [ZnCl4]2− tetrahedra. Solid state 13C CP-MAS-NMR spectra show seven isotropic resonances, confirming the existence of seven non-equivalent carbon atoms which are consistent with the solid state structure determined by X-ray diffraction. Impedance spectroscopy study, reported for single crystal and powder samples, reveals that the conduction in the material is due to a hopping process along the [100] direction. [Copyright &y& Elsevier]