Vibrational study,phase transitions and electrical properties of 4-benzylpyridinium monohydrogenselenate

The title compound C₆H₅CH₂C₅H₄NH⁺·HSeO₄⁻ crystallizes in the orthorhombic system with the space group Pbca and the following unit cell dimensions: a=27.449(5) Å; b=10.821(6) Å and c=8.830(1) Å.The structure consists of infinite parallel two-dimensional planes built of HSeO₄⁻ anions and C₆H₅CH₂C₅H₄NH⁺ cations mutually.Differential scanning calorimetry study on 4-benzylpyridinium monohydrogen-selenate was carried out. A high temperature second order phase transition at 363 K was found and characterized by electric measurements. The Raman of polycrystalline sample has been recorded at different temperature between 297 and 373 K.The conductivity relaxation parameters associated with some H⁺ conduction have been determined from an analysis of the M′′/M′′_max spectrum measured in a wide temperature range. An appearance of the superionic phase transition in 4-BSe is closely related to a liberation or even a rotation increase of HSeO₄⁻ groups with heating.     

Synthesis,structural characterization,Hirshfeld surface analysis,spectroscopic and ferroelectric properties studies of 4-methylbenzylammonium sulfate

Single crystals of 4-methylbenzylammonium sulfate were grown in an aqueous solution at room temperature. The grown compound is characterized by spectroscopic, thermal, and dielectric studies and its structure was determined by single-crystal X-ray diffraction analysis. Its crystal structure is described as a three-dimensional network where the sulfate anions (HSO₄^?) are interconnected through H-bonds to form anionic layers between which the 4-methylbenzylammonium cations are located. The hydrogen bonding network connecting the different components is given. Hirshfeld surface analysis was performed to visualize, explore and quantify intermolecular interactions in the crystal lattice. This analysis revealed the presence of H…C/H…C, C…O/O…C intermolecular interactions and O…O, H…H short contacts in the crystal. X-ray, structural and electrical results are correlated. The kind of the observed conduction is protonic by translocation. Differential scanning calorimetry (DSC) shows that this material presents a reversible phase transition at 390 K, confirmed by the dielectric permittivity study.     

Structural study,intermolecular interactions in view of X-ray and Hirshfeld surface analysis,DSC characterization,and electrical properties of <Emphasis Type="Italic">bis</Emphasis>-(4-benzylpyridinium) tetrabromozincate

The synthesis and crystal structure of the bis-(4-benzylpyridinium) tetrabromozincate(II) “(4-BP)₂[ZnBr₄]” salt are reported in the present paper. After an X-ray investigation, it has been shown that the title compound belongs to the centrosymmetric monoclinic system at 296 K, in the space group P2₁/n with the following lattice parameters a = 15.0764(8) Å, b = 22.5575(12) Å, c = 16.0739(9) Å, and β = 93.887(3)°. The FT-IR and Raman spectra confirm the presence of both cationic and anionic parts. The crystal packing is governed by an extensive network: N–H…Br, (N: pyridinium), C–H…Br hydrogen bonds, π…π, and C–H…π stacking between identical 4-BP (aromatic–aromatic), in which they may be effective in the stabilization of the crystal structure. Moreover, Hirshfeld surface analysis was used for visually analyzing intermolecular interactions in crystal structures. The phase transitions at T = 323 K have been confirmed by the differential scanning calorimetry. The electrical technique was measured in the 209 Hz–5-MHz frequency range and 298–393-K temperature intervals. The evolution of the dielectric constant as a function of frequency and temperature proved the presence of a first-order phase transition at 323 K.

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Synthesis,crystal structure,spectroscopic characterization and optical properties of bis(4-acetylanilinium) tetrachlorocobalt (II)

The chemical preparation, crystal structure, spectroscopic investigations and optical features are given for a novel organic–inorganic hybrid material [C₈H₁₀NO]₂CoCl₄.The compound is crystallized in the orthorhombic space group Cmca, with the following unit cell parameters: a=19.461(2) Å, b=15.523(2) Å, c=13.7436(15) Å, and Z=8. The atomic arrangement shows an alternation of organic and inorganic layers along the b-axis. The cohesion between these entities is performed by N–H…Cl and N–H…O hydrogen bonds and π–π stacking interactions.Infrared and Raman spectra at room temperature are recorded in the 4000−400 and 4000−0 cm⁻¹ frequency regions, respectively and analyzed on the basis of literature data. This study confirms the presence of the organic cation [C₈H₁₀NO]⁺ and of the [CoCl₄]²⁻ anion. UV–vis spectroscopy results showed the indirect transition with band gap energy 2.98 eV.     

Weak and strong hydrogen bonds conducting the supramolecular framework of 1-butyl-3-(1-naphthoyl)thiourea: crystal structure,vibrational studies,DFT methods,Pixel energies and Hirshfeld surface analysis

A detailed structural and spectroscopic study of a new thiourea derivative 1-butyl-3-(1-naphthoyl)thiourea (1) is presented with the assistance of theoretical calculations. The X-ray diffraction structure analysis reveals a planar carbonylthiourea group, favoured by intra-molecular NH···O bond. The compound is arranged in the lattice as NH···O and NH···S bonded polymeric ribbons, that extend along the crystal b-axis. Molecular pairs involving N–H···S hydrogen bonds are a dominant contribution to packing stabilisation coming from coulombic component. Hirshfeld surfaces and two-dimensional-fingerprint plots show different intermolecular contacts and its relative contributions to total surface in each compound. The AIM approach shows the nature and strength of the strong and weak intramolecular interactions and the solvent effect, while NBO analysis reveals that the sulphur atom is responsible for the higher hyperconjugative stabilising energy.     

Dielectric properties and study of AC electrical conduction mechanisms by non-overlapping small polaron tunneling model in Bis(4-acetylanilinium) tetrachlorocuprate(II) compound

In the present work, the synthesis and characterization of the Bis(4-acetylanilinium) tetrachlorocuprate(II) compound are presented. The structure of this compound is analyzed by X-ray diffraction which confirms the formation of single phase and is in good agreement the literature. Indeed, the Thermo gravimetric Analysis (TGA) shows that the decomposition of the compound is observed in the range of 420–520 K. However, the differential thermal analysis (DTA) indicates the presence of a phase transition at T=363 k. Furthermore, the dielectric properties and AC conductivity were studied over a temperature range (338–413 K) and frequency range (200 Hz–5 MHz) using complex impedance spectroscopy. Dielectric measurements confirmed such thermal analyses by exhibiting the presence of an anomaly in the temperature range of 358–373 K. The complex impedance plots are analyzed by an electrical equivalent circuit consisting of resistance, constant phase element (CPE) and capacitance. The activation energy values of two distinct regions are obtained from log σT vs 1000/T plot and are found to be E=1.27 eV (T<363 K) and E=1.09 eV (363 K<T).The frequency dependence of ac conductivity, σ_ac, has been analyzed by Jonscher's universal power law σ(ω)=σ_dc+Aω^s. The value of s is to be temperature-dependent, which has a tendency to increase with temperature and the non-overlapping small polaron tunneling (NSPT) model is the most applicable conduction mechanism in the title compound.     

Synthesis,structural characterization,spectroscopic, thermal,dielectric and Hirshfeld surface analysis of 1-(2-methoxyphenyl)piperazinium chloranilate

The new compound 1-(2-methoxyphenyl)piperazinium chloranilate (MPP.CA) was synthesized and studied by the single crystal X-ray diffraction method. Its structure was confirmed by infrared spectroscopy. The crystal structure consists of ribbons of chloranilate anions and 1-(2-methoxyphenyl)piperazinium cations linked together by NH…O hydrogen bonds. Two protons are transferred from a chloranilic acid molecule to the nitrogen of the piperazine in this structure. Measurements of AC conductivity as a function of frequency at different temperatures indicated the hopping conduction mechanism; in addition, the variation of dielectric constant as a function of T confirmed the transition phase indicated by the differential scanning calorimetry (DSC). The physico-chemical properties, UV-Vis, DSC and dielectric properties are described. Hirshfeld surface analyzes all the intermolecular interactions involved within the structure, which are important to stabilize the structure.     

Synthesis,crystal structure,thermal analysis,and electrical properties of bis tetrapropylammonium hexachloro-dizincate compound

The present paper accounts for the synthesis, crystal structure, differential scanning calorimetry, vibrational study, and electrical properties of the [N(C₃H₇)₄]₂Zn₂Cl₆ compound. The latter is crystallized at room temperature in the triclinic system ( $ P\overline{1} $ space group) with the following unit cell parameters: a?=?13.736(2)Å, b?=?17.044(3)Å, c?=?17.334(2)Å, α?=?68.30(2)°, β?=?75.14(2)°, and γ?=?84.93(3). The atomic arrangement can be described by alternating organic and inorganic layers parallel to the (001) plan, made up of [N(C₃H₇)₄]⁺ groups and [Zn₂Cl₆]^2? dimers, respectively. In crystal structure, the inorganic layer, built up by Zn₂Cl₆ dimers, is connected to the organic ones through van der Waals interaction in order to build cation–anion–cation cohesion. The infrared and Raman studies confirm the presence of the organic group tetrapropylammonium and the Zn₂Cl₆ anion. Concerning the differential scanning calorimetry, it revealed two reversible solid–solid phase transitions of first order: at 327/324 K and 347/343 K (heating/cooling). Besides, the impedance spectroscopy study, reported in the sample, reveals that the conduction in the material is due to a hopping process. Regarding the temperature dependence of the dc conductivity, it suggests Arrhenius type: σ _dc T?=?B ?exp(?E _a /kT). The tetrapropylammonium cations appeared to be the most sensitive to the phase transition.     

Crystal growth, structure and electrical properties of thorium phosphorosulfide

Single crystals of thorium phosphorosulfide have been grown by the chemical vapour transport method. The X-ray diffraction examination showed that the unit cell of the crystals belongs to a tetragonal system of the PbFCl-type structure. The basal plane resistivity ρ(300 K)=64 μΩ cm and thermoelectric power S(300 K)=−7.7 μV/K, examined between 0.4 and 315 K, show metallic behaviour.     

Structural,electrical and dielectric studies of nanocrystalline LiMnPO4 particles

Olivine-structured LiMnPO₄ nanoparticles were prepared by microwave-assisted solvothermal method. The as obtained LiMnPO₄ sample was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and impedance spectroscopy techniques. The XRD pattern confirms the formation of LiMnPO₄ phase with an orthorhombic structure. The electrical conductivity of the sample at room temperature is found to be 1.2654?×?10^?7 S cm^?1. Dielectric spectra show an increase in dielectric constant with increase of temperature. The dielectric loss spectra reveal the predomination of DC conduction in the sample. The modulus studies indicate the non-Debye nature of the sample which corresponds to the distribution of elements in the sample. Galvanostatic battery testing showed that LiMnPO₄ nanoparticles displayed good cycleability in 30 cycles.     

Crystal growth, stability and photoluminescence studies of tetra aqua diglycine magnesium (II) hexa aqua magnesium (II) bis sulfate crystal

Single crystals of tetra aqua diglycine magnesium (II) hexa aqua magnesium (II) bis sulfate have been grown from saturated aqueous solution by slow evaporation solution growth technique. The solubility of the title compound in water at various temperatures has been determined. Single-crystal X-ray diffraction analyses reveal that the title compound crystallizes in triclinic system with space group P1?. Fourier transform infrared spectral analyses confirm the presence of functional groups in the grown crystal. The thermal stability of the grown crystal has been investigated by thermogravimetric and differential scanning calorimetric analysis. It indicates that the material is stable upto 100 °C. The crystalline perfection of the grown crystal has been evaluated by high-resolution X-ray diffraction technique. Vickers microhardness measurements indicate the mechanical strength of the grown crystal. Photoluminescence of the grown crystal has been investigated and it reveals that the crystal has blue-violet fluorescence emission.     

Crystal structure and thermochemical properties of phase change materials bis(1-octylammonium) tetrachlorochromate

A new crystalline complex (C₈H₁₇NH₃)₂CdCl₄(s) (abbreviated as C₈Cd(s)) is synthesized by liquid phase reaction. The crystal structure and composition of the complex are determined by single crystal X-ray diffraction, chemical analysis, and elementary analysis. It is triclinic, the space group is P-1 and Z = 2. The lattice potential energy of the title complex is calculated to be U_POT (C₈Cd(s))=978.83 kJ·mol^-1 from crystallographic data. Low-temperature heat capacities of the complex are measured by a precision automatic adiabatic calorimeter over a temperature range from 78 K to 384 K. The temperature, molar enthalpy, and entropy of the phase transition for the complex are determined to be 307.3± 0.15 K, 10.15± 0.23 kJ·mol^-1, and 33.05± 0.78 J·K^-1·mol^-1 respectively for the endothermic peak. Two polynomial equations of the heat capacities each as a function of temperature are fitted by the least-square method. Smoothed heat capacity and thermodynamic functions of the complex are calculated based on the fitted polynomials.     

Spectral,X-ray diffraction,surface morphological and thermal studies of gamma-irradiated potassium bis(oxalato)zincate(II)dihydrate

ABSTRACT

Potassium bis(oxalato)zincate(II)dihydrate was prepared and characterized. The sample was irradiated with ⁶⁰Co gamma rays up to 900?kGy. Infrared, Raman and photoluminescence spectra, X-ray diffraction pattern, surface morphology by AFM and SEM and non-isothermal decomposition of the complex were studied before and after irradiation. Spectral studies suggested significant radiation damage. X-ray diffraction studies showed reduction in unit cell volume and average crystallite size. Both unirradiated and irradiated samples of the complex belong to the hexagonal crystal system. Surface morphology of the complex changed upon irradiation. Thermal decomposition was enhanced.     

The geometrical and vibrational properties of the Rh(111) surface

Low-energy electron diffraction (LEED) data have been used to characterize the clean Rh(111) surface. The surface geometry, the degree of surface relaxation, and the Debye temperature have been determined. In the Debye temperature measurement, specular LEED beam intensities were monitored as a function of temperature over a range of electron energies from approximately 30 to 1000 eV. It was found that the bulk Debye temperature is 380 ± 23 K, and the normal component of the Debye temperature at the lowest electron energy used is 197 ± 12 K. The Rh(111) surface relaxation has been determined both by a convolution-transform analysis and by dynamical calculations. Within experimental error, neither expansion nor contraction of the topmost layer has been detected. The results of the convolution-transform analysis of specular beams at two angles of incidence and of a nonspecular beam at normal incidence suggest an expansion of the topmost layer of 3 ± 5% of the bulk layer spacing. In agreement with this, comparisons between the results of the dynamical calculation and experimental data for five nonspecular beams at normal incidence suggest that the surface layer relaxes by 0 ± 5%. In addition, the dynamical calculations indicate that the topmost layer maintains an fcc structure.     

Crystal structure and electrical properties study of 4-aminopyridinium chloridobismuthate (III) (C5N2H7)4.HBi2Cl11

The crystal structure of (C₅N₂H₇)₄.HBi₂Cl₁₁ has been determined at room temperature by single crystal X-ray diffraction. The compound crystallizes in the triclinic system with Pī space group. The crystal structure consists of two asymmetric inequivalent molecules of 4-aminopyridinium and anionic HBi₂Cl₁₁ chains. The HBi₂Cl₁₁ anionic chains stacked along the a-axis are formed with Bi₂Cl₁₁ dimers connected to each other via hydrogen atoms. The crystal packing is stabilized with N–H...Cl hydrogen bonds connecting aminopyridinium units to the HBi₂Cl₁₁ anionic chains. The title compound exhibits an order–disorder phase transition at 338 K. The AC electrical conductivity properties of (C₅N₂H₇)₄.HBi₂Cl₁₁ compound have been investigated by means of impedance spectroscopy measurements over wide ranges of frequencies and temperatures, 200 Hz to 5 MHz and 303 to 418 K, respectively. Detailed analysis of the impedance spectrum suggests that the electrical properties of the material are strongly temperature dependent. The frequency-dependent conductivity data were fitted in the Jonscher's law: $ \sigma \left( \omega \right) = \sigma (0) + A{\omega^n} $ . The nature of variation of DC conductivity suggests Arrhenius type of electrical conductivity.     

Crystal growth, FTIR and thermal characterization of bis(ethyltriphenylphosphonium) tetrabromomanganate(II) dihydrate crystals

Single crystals of a novel compound, bis(ethyltriphenylphosphonium) tetrabromomanganate(II) dihydrate (BTP-Mn) were grown by solution growth-slow evaporation technique from aqueous solution of the compound at ambient temperature. The grown crystals were characterized by elemental analysis, powder X-ray diffraction, thermal analysis, nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infra-red spectroscopy (FTIR) techniques. The chemical composition of the compound was revealed by elemental analysis and its crystallinity was confirmed by powder X-ray diffraction. Thermal analysis confirmed that the compound was stable up to 125°C. The various kinds of protons and carbons present in the compound were confirmed by ¹H NMR and ¹³C NMR technique respectively and the presence of phosphorous was confirmed by ³¹P NMR spectrum in the compound. The modes of vibration of different molecular groups present in the compound were identified by FTIR spectral analysis. The second harmonic generation behaviour was tested by Nd:YAG laser source.     

Studies of structure, thermal, and electrical properties for Cs 5 H 3 (SO 4 ) 4 crystal

Electrical conductivity, differential scanning calorimetry, and X-ray diffraction measurements were performed on a pentacesium trihydrogen tetrasulfate, Cs₅H₃(SO₄)₄, crystal. The transition entropy at a superionic phase transition and the activation energy of proton migrations in the superionic phase were determined to be 58.2 J K⁻¹ mol⁻¹ and 0.48 eV, respectively. The crystal structure of Cs₅H₃(SO₄)₄ at room temperature was refined. The electrical conduction in Cs₅H₃(SO₄)₄ was discussed with the refined structure.