Ab Initio Estimation of NbF−
 6 , NbClF2−
 6 , and NbF2−
 7 Complexes Stability in Alkali Chloride Melts

Kremenetsky, V. G.; Kuznetsov, S. A.; Kremenetskaya, O. V.; Soloviev, V. V.; Chernenko, L. A.; Fofanov, A. D.

doi:10.1515/zna-2010-1112

Cited by 7 publications

(5 citation statements)

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“…Nevertheless, it is desirable to perform a control calculation of systems II as it allows us to occasionally reveal a change in the composition of the first coordi nation shell of the complex forming atom due to the interaction of the starting complex with the external environment [36]. Figure 9 shows the optimized structures of the sys tems of type I.…”

Section: Quantum Chemical Calculationsmentioning

confidence: 99%

Electrochemical and quantum-chemical studies of chromium(III,II) fluoride complexes in alkali chloride melts

2014

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815Previously, we studied the effect of the second coordination sphere on k s in chloride melts [17,18]. The NaCl-KCl-CrCl 3 , KCl-CrCl 3 , and CsCl-CrCl 3 systems were studied. It was shown that the standard rate constants of charge transfer increased at elevated Abstract-The standard rate constants (k s ) of charge transfer on a glass carbon electrode were determined for the Cr(III)/Cr(II) redox pair in the NaCl-KCl-K 3 CrF 6 , KCl-K 3 CrF 6 , and CsCl-K 3 CrF 6 systems at 973-1173 K by cyclic voltammetry. The k s constant was found to increase at elevated temperatures and the follow ing nonmonotonic dependence of k s on the nature of the outer spheric cation was found: k s (CsCl) > k s (NaCl-KCl) > k s (KCl). On the basis of quantum chemical data for the M 3 CrF 6 + 18MCl (M = Na, K) model systems, it was shown that the complex chromium particles with four or five outer spheric sodium or potassium cations had maximum thermodynamic stability. Quantum chemical calculations were performed to interpret the experimental data on the effect of the second coordination sphere of the complexes on the standard charge transfer rate constants.

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Section: Quantum Chemical Calculationsmentioning

confidence: 99%

Electrochemical and quantum-chemical studies of chromium(III,II) fluoride complexes in alkali chloride melts

2014

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“…When simulating electrochemical reactions for niobium-containing systems, the values of the reorganization energy Er of the solvate shell of EAP were calculated in the same way as for tungstate-containing systems. Analysis of the values of activation energies (for the sake of convenience/activation barriers δ) for [Nb(V)F7] 2 -+ ē  [Nb(IV)F7] 3 (in accordance with the experiment [9,10]) shows a significant influence of the acid-base properties of an environment on the reactivity of EAP, indicating the advantage of electroreduction of {Mnm + [NbF7] 2 -} (mn -2)+ particles, compared to the direct reduction of the heptafluoroniobate-ion.…”

Section: Results and Their Discussionmentioning

confidence: 72%

The Influence of Nanosized Active Particles of the Melt and the Electrode Surface on Charge Transfer Processes at the Electrode/Melt Interface

Solianyk¹

2022

J. Nano- Electron. Phys.

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By using methods of quantum chemistry, in order to study a mechanism of electrode processes at the electrode/melt interface, calculations of reorganization energy were made within a model of conductive ellipsoids, which generalizes the Marcus model for a case when reagents are substantially non-spheric. It was ascertained that a value of reorganization energy of a dissolvent hardly varies at all intervals of distances between an electrode surface and a reagent and decreases substantially with an increase in a reagent charge. The values of activation energy for charge transfer at the electrode/melt interface were calculated. A decrease in the values of activation energy for charge transfer between a cathode surface and particles of a melt was established. The values of molecular orbital energies were calculated for a fragment of an electrode surface and active complexes of model melts. Based on the analysis of activation energy values and values of energy of highest occupied and lowest unoccupied molecular orbitals of the interacting structures, a conclusion was made about the essential role of a cationic composition of an electrolyte in the processes of electroreduction at the cathode. The analysis of the obtained theoretical results allows us to formulate the conditions for the occurrence of surface conductivity of the dielectric in the salt melt. A presumption was made that a selection of an electrolyte composition allowed controlling the rate of redox reactions at the electrode/melt interface without prior metallization of the dielectric i.e., a targeted change in the cationic composition of a melt makes it possible to achieve concurrence of energy levels of the electrode surface and the active complex, thereby enabling control over the synthesis of nanoparticles at the cathode. It was established that the mechanism of electrode processes at the electrode/melt interface is based on a shift in the Fermi level of a cluster of a solid-state body surface as well as equality of energies of marginal molecular orbitals of a pre-reaction complex and a cluster, which are determining factors in heterogeneous redox reactions at the surface of a dielectric immersed in a corresponding ionic melt.

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“…This accounts for the consistency (at the qualitative level) between the calculated parameters for systems I and their experimental analogues, and allows us to consider the conclusions based on studying systems I as a valid initial estimate. Nevertheless, it is expedient to perform the control calculation of the structure of systems II since it reveals, in some specific cases, the change in the composition of the first ligand shell of the complex-forming atom caused by the interaction of the initial complex in systems I with the outer environment (9). As distinct from systems I, for systems II, the interaction energy of the second CS (M) n with the complex and the rest of the system can be calculated directly.…”

Section: Resultsmentioning

confidence: 99%

Comparison of Some Structural Parameters of the Model Systems nM⁺[CrX₆]^3- and 3M⁺[CrX₆]^3- + 18MCl (M–Na, K, Cs; X–F, Cl; n=1–6)

Kuznetsov

Kremenetsky

2014

ECS Trans.

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To verify conclusions obtained for the (M + ) n •[CrX 6 ] model systems (type I), where M = Na, K, Cs and X = F, Cl, computations of the interaction energy of fragments with various compositions have been carried out in extended model systems (type II), which contain additional 18MX. It has been found that in systems II the composition of the second coordination sphere of the most stable fragments coincides with the outer-sphere composition of the most stable particles in systems I, or contains one more cation. Both types of systems are used in quantum-chemical modeling of the charge transfer processes.

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Ab Initio Estimation of NbF⁻ ₆ , NbClF²⁻ ₆ , and NbF²⁻ ₇ Complexes Stability in Alkali Chloride Melts

Cited by 7 publications

References 1 publication

Electrochemical and quantum-chemical studies of chromium(III,II) fluoride complexes in alkali chloride melts

Electrochemical and quantum-chemical studies of chromium(III,II) fluoride complexes in alkali chloride melts

The Influence of Nanosized Active Particles of the Melt and the Electrode Surface on Charge Transfer Processes at the Electrode/Melt Interface

Comparison of Some Structural Parameters of the Model Systems nM⁺[CrX₆]^3- and 3M⁺[CrX₆]^3- + 18MCl (M–Na, K, Cs; X–F, Cl; n=1–6)

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Ab Initio Estimation of NbF− 6 , NbClF2− 6 , and NbF2− 7 Complexes Stability in Alkali Chloride Melts

Cited by 7 publications

References 1 publication

Electrochemical and quantum-chemical studies of chromium(III,II) fluoride complexes in alkali chloride melts

Electrochemical and quantum-chemical studies of chromium(III,II) fluoride complexes in alkali chloride melts

The Influence of Nanosized Active Particles of the Melt and the Electrode Surface on Charge Transfer Processes at the Electrode/Melt Interface

Comparison of Some Structural Parameters of the Model Systems nM+[CrX6]3- and 3M+[CrX6]3- + 18MCl (M–Na, K, Cs; X–F, Cl; n=1–6)

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Ab Initio Estimation of NbF⁻ ₆ , NbClF²⁻ ₆ , and NbF²⁻ ₇ Complexes Stability in Alkali Chloride Melts

Comparison of Some Structural Parameters of the Model Systems nM⁺[CrX₆]^3- and 3M⁺[CrX₆]^3- + 18MCl (M–Na, K, Cs; X–F, Cl; n=1–6)