Ac conductivity, electric modulus analysis, dielectric behavior and Bond Valence Sum analysis of Na3Nb4As3O19 compound

Chérif, Saïda Fatma; Chérif, Amira; Dridi, Wassim; Zid, Mohamed Faouzi

doi:10.1016/j.arabjc.2020.04.003

Cited by 66 publications

(13 citation statements)

References 40 publications

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“…The structural characteristics of the product confirmed the existence of proton transfer at O 4 H and six coordination bonds (Na + ← O bonds) in its unit cell (Figure A and Figure A). The Na + bond valence sum value calculated from the crystallographic data is 1.1 (Section S9), higher than the formal oxidation state of +1, supporting the fact that the Na–O bonds are more covalent. , To further confirm that PUE-Na is a chelate hydrate rather than a salt hydrate, the complexation between PUE – and Na + in the aqueous solution was investigated by the titration of NaOH solution with PUEM …”

Section: Discussionmentioning

confidence: 89%

“…The Na + bond valence sum value calculated from the crystallographic data is 1.1 (Section S9), higher than the formal oxidation state of +1, supporting the fact that the Na−O bonds are more covalent. 66,67 To further confirm that PUE-Na is a chelate hydrate rather than a salt hydrate, the complexation between PUE − and Na + in the aqueous solution was investigated by the titration of NaOH solution with PUEM. 19 In the potentiometric titration process using ion-selective electrodes, the drop of EMF for a specific ion could be ascribed to the interaction between different cations and anions in solution.…”

Section: Discussionmentioning

confidence: 99%

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Puerarin-Na Chelate Hydrate Simultaneously Improves Dissolution and Mechanical Behavior

et al. 2021

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Puerarin monohydrate (PUEM), as the commercial solid form of the natural anti-hypertension drug puerarin (PUE), has low solubility, poor flowability, and mechanical properties. In this study, a novel solid form as PUE-Na chelate hydrate was prepared by a reactive crystallization method. Crystal structure analysis demonstrated that PUE-Na contains PUE − , Na + , and water in a molar ratio of 1:1:7. It crystallizes in the monoclinic space group P2 1 , and Na + is linked with PUE − and four water molecules through Na + ← O coordination bonds. Another three crystal water molecules occupy channels along the crystallographic b-axis. Observing along the b-axis, the crystal structure features a distinct tubular helix and a DNA-like twisted helix. The complexation between Na + and PUE − in aqueous solution was confirmed by the Na + selective electrode, indicating that PUE-Na chelate hydrate belongs to a type of chelate rather than organic metal salt. Compared with PUEM, PUE-Na exhibited a superior dissolution rate (i.e., ∼38-fold increase in water) owing to its lower solvation free energy and clear-enriched exposed polar groups. Moreover, PUE-Na enhanced the tabletability and flowability of PUEM, attributing to its better elastoplastic deformation and lower-friction crystal habit. The unique PUE-Na chelate hydrate with significantly enhanced pharmaceutical properties is a very promising candidate for future product development of PUE.

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Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Puerarin-Na Chelate Hydrate Simultaneously Improves Dissolution and Mechanical Behavior

et al. 2021

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“…ω ω < ′′ ) to short-range motion, when the charge carriers are not able to follow the fast changes of the oscillating electrical field. [23,38,39] The higher value of max M ω ′′ for the sample with 150 µL of PANa suggests that the frequency range for nonlocal motion is wider.…”

Section: Resultsmentioning

confidence: 98%

“…Furthermore, M″ maximum value reflects the transition from long‐range (

\omega &lt; \omega _{\max }^{{\rm{M}}\prime \prime }

) to short‐range motion, when the charge carriers are not able to follow the fast changes of the oscillating electrical field. [ 23,38,39 ] The higher value of

\omega _{\max }^{{\rm{M}}\prime \prime }

for the sample with 150 µL of PANa suggests that the frequency range for non‐local motion is wider.…”

Section: Resultsmentioning

confidence: 99%

The Role of Superadsorbent Polymers on Covalent Organic Frameworks‐Based Solid Electrolytes: Investigation of the Ionic Conductivity and Relaxation

Gullace

Cusin

Richard

et al. 2023

Adv Materials Inter

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The scarcity of fossil fuels calls for immediate action toward the development of clean and renewable energy resources. In this context, proton exchange membrane fuel cells (PEMFCs) are gaining ever‐increasing attention as clean technology. Although covalent organic frameworks (COFs) do not usually exhibit high intrinsic proton conductivity (σ), they have been recently proposed as solid polymer electrolytes in PEMFCs, thanks to their high crystallinity and stability to acids and bases. Here, a simple strategy is presented to improve the performance of poor COF‐based proton conductors through addition of sodium polyacrylate (PANa) superadsorbent polymer. Electrochemical impedance spectroscopy investigations after activation at high temperature and relative humidity (RH) provide insights into the role of PANa, whose presence is key to preserve high σ at low RH. The humidity‐dependent X‐ray diffraction study reveals a strengthening of the stacking interaction along the COF (100) plane direction with increasing humidity, through the formation of H‐bonding, thus promoting proton hopping. The study of the dielectric properties as a function of PANa content enables to determine a Debye relaxation regime for the COF/PANa blend with a maximum relaxation frequency of 1513 and 6606 Hz for the pristine COF and the COF/PANa blend, respectively, at their maximum operating temperatures.

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“…[ 24 ] These peculiarities cannot be related to any kind of phase transformation as no phase transition has been noticed in ZrO 2 and mullite‐based ceramic composites in this temperature range. [ 25 ] The rise in loss factor and permittivity with temperature in Y 2 O 3 ‐PMZ composites can be attributed to thermally generated oxygen vacancies or point defects due to the substitution of Al 3+ in place of Si 4+ and Y 3+ in place of Zr 4+ in these composites. [ 26 ] However, the loss tangent is higher in porous Y 2 O 3 ‐CMZ composite than that of Y 2 O 3 ‐PMZ composite as the pores act as defects and enhance the conductivity process in the material leading to a high dielectric loss factor.…”

Section: Resultsmentioning

confidence: 99%

AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO₂@Mullite Composite

Biswal,

Mishra

2023

Cryst. Res. Technol.

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The addition of 8 mol% of Y2O3 to the ZrO2@mullite composites stabilizes the metastable tetragonal phase of ZrO2 in conventional and plasma‐sintered Y2O3‐stabilized ZrO2@mullite composites. A fused, highly dense, and interconnected microstructure is formed in the case of plasma‐sintered Y2O3 stabilized ZrO2@mullite composite. At 1 MHz frequency, the room temperature and tanδ of (10.37 and 2.06) is obtained for the conventional Y2O3 stabilized ZrO2@mullite composite and that of (38.8 and 4.02) is observed for the plasma sintered Y2O3 stabilized ZrO2@mullite composite. The substitution of Y3+ in place of Zr4+ creates sufficiently large oxygen vacancies at the grain boundary regions of these composites endowed mostly with the ZrO2 phase. In conventional Y2O3‐ ZrO2@mullite composites, both dielectric relaxation as well as conductivity relaxation are observed due to the dynamic motion of dipoles and relaxation due to the presence of defect states and porous structures. This leads to higher grain boundary conductivity than the grain conductivity of these composites. Thermally activated conduction mechanisms exhibited in these composite materials are projected from the complex impedance and modulus analysis. The conventional and plasma sintered Y2O3‐ ZrO2@mullite composite has an optical bandgap of 3.26 and 3.58 eV, respectively.

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Ac conductivity, electric modulus analysis, dielectric behavior and Bond Valence Sum analysis of Na3Nb4As3O19 compound

Cited by 66 publications

References 40 publications

Puerarin-Na Chelate Hydrate Simultaneously Improves Dissolution and Mechanical Behavior

Puerarin-Na Chelate Hydrate Simultaneously Improves Dissolution and Mechanical Behavior

The Role of Superadsorbent Polymers on Covalent Organic Frameworks‐Based Solid Electrolytes: Investigation of the Ionic Conductivity and Relaxation

AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO₂@Mullite Composite

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Ac conductivity, electric modulus analysis, dielectric behavior and Bond Valence Sum analysis of Na3Nb4As3O19 compound

Cited by 66 publications

References 40 publications

Puerarin-Na Chelate Hydrate Simultaneously Improves Dissolution and Mechanical Behavior

Puerarin-Na Chelate Hydrate Simultaneously Improves Dissolution and Mechanical Behavior

The Role of Superadsorbent Polymers on Covalent Organic Frameworks‐Based Solid Electrolytes: Investigation of the Ionic Conductivity and Relaxation

AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO2@Mullite Composite

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Product

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About

AC Conduction Mechanism and Impedance Analysis of Conventional and Plasma‐Sintered Yttria‐Stabilized ZrO₂@Mullite Composite