Mechanismus der Elektroreduktion von V(+V)

In papers containing data about electrode reactions of oxo-ions there are great differences concerning the mechanisms of the electrode reactions. In this work the electrode reaction of VO₃ ^– is described and interpreted. All effects observed at the reduction of VO₃ ^– are in accord with the proposed theory.

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Mit 1 Abbildung     

Birthday of Professor V.V. Kuznetsov

Chronicle

Birthday of Professor V.V. Kuznetsov     

Lepidoide V

Zusammenfassung Fu?end auf Arbeiten vonH. Kautsky und Mitarb., die die lepidoide Struktur der durch Ausfrieren aus demGraham- Sol erh?ltlichen Kiesels?ure (H₂Si₂O)_5n nachgewiesen haben, wird das Kiesels?uresol selbst im wesentlichen mittels viskosimetrischer und chemischer Methoden untersucht. Es folgt aus diesen Messungen, da? die einzelnen Kolloidteilchen des Sols v?llig unabh?ngig voneinander sind und aus Netzen der auch den Schichtsilikaten zugrunde liegenden Kiesels?ure (H₂Si₂O₅) _n bestehen. Diese Netze, aus Monokiesels?ure durch gerichtete zweidimensionale Kondensation gebildet, werden über Si-O-Si-Bindungen miteinander verknüpft. Durch die Beweglichkeit der Kiesels?urenetze an den Si-O-Si-Knüpfstellen ist eine weitgehende Form?nderung der Kolloidteilchen m?glich, die sich z. B. in der Abh?ngigkeit der Viskosit?t und der Sedimentationskonstante der Sole vom p_H ?u?ert. Es wird nachgewiesen, da? im feuchten Kiesels?uregel das gleiche Strukturprinzip wie im Sol verwirklicht ist, so da? die übertragung obiger Modellvorstellung auch auf das entw?sserte Produkt mit gro?er Wahrscheinlichkeit erlaubt ist.     

Beryllium V

Ohne Zusammenfassung     

On the Anniversary of V. V. Lunin

Russian Journal of Physical Chemistry A -     

Numerical inversion of the V—V master equation

The information-theoretic approach to vibrational—vibrational (V—V) energy transfer is employed to invert numerically the V—V master equation for vibrational enregy exchange between CO molecules.     

Investigation on Concentrated Ⅴ（Ⅳ）/Ⅴ（Ⅴ） Redox Reaction by Rotating Disc Voltammetry

The kinetic characteristics of the concentrated Ⅴ（Ⅳ）/Ⅴ（Ⅴ） couple have been studied at a glassy carbon electrode in sulfuric acid using rotating-disc electrode and cyclic voltammetry. The kinetics of the Ⅴ（Ⅳ）/Ⅴ（Ⅴ） redox couple reaction was found to be electrochemically quasi-reversible with the slower kinetics for the Ⅴ（Ⅴ） reduction than that for the Ⅴ（Ⅳ） oxidation. And, dependence of diffusion coefficients and kinetic parameters of Ⅴ（Ⅳ） species on the Ⅴ（Ⅳ） and H2SO4 concentration was investigated. It is shown that the concentration of active species Ⅴ（Ⅳ） should be over 1 mol·L^-1 for the redox flow battery application. Further, with increasing the Ⅴ（Ⅳ） and H2SO4 concentration, the diffusion coefficients of Ⅴ（Ⅳ） were gradually reduced whereas its kinetics was improved considerably, especially in the case of Ⅴ（Ⅳ） and H2SO4 up to 2 and 4 mol·L^-1.     

含钒(IV)和钒(V)的钨锗混合价杂多酸盐的合成及其结构表征

报道了含钒(IV)和钒(V)的钨锗混合价杂多酸盐的合成、电子吸收光谱及单电子还原态的ESR谱。α-和β-[HGeV^I^VV2^VW9O40]^7^-的溶液ESR谱是由40余条超精细线组成的, 表明在阴离子中3个VO6八面体是角顶共用, 且其中一个桥氧原子是质子化的。     

V—V,V—R,T transfer in triatomic molecules. Results for ONF

The laser-induced fluorescence technique is applied to study vibrational energy transfer in pure ONF. Different vibrational modes are excited using a TEA CO₂ laser and the rise and fall of ν₁, ν₂, and (ν₁ + ν₃) fluorescence is detected. These measurements yield a detailed picture of V—V exchange in the region of the fundamentals and V—R,T transfer to rotational and translational degrees of freedom. The relaxation behavior of ONF is compared with that of ONCI and other triatomic molecules.     

Mixed halodicyclopentadienyl-niobium(V) and -tantalum(V)

Oxidation of (η⁵-C₅H₅)₂MCl (M = Nb, Ta) with 1 mol of Cl₂, Br₂ or I₂ gives (η⁵-C₅H₅)₂MClX₂ whereas the reaction with an excess of the halogen gives the cationic complexes [η⁵-C₅H₅)₂MClX]⁺ X₃^? (X = Br, I). Similar oxidation of (η⁵-C₅H₅)₂MCl₂ with 0.5 mol of halogen gives (η⁵-C₅H₅)₂MCl₂X complexes, but if the halogen is used in excess cationic [η⁵-C₅H₅)₂MCl₂]⁺ X₃^? (X = Br, I; M = Ta and X = I, M = Nb) are obtained. All these complexes can also be obtained simultaneously by oxidizing (η⁵-C₅H₅)₄M₂Cl₃, and the separation is fairly easy in most cases. Conductivity and IR and NMR data are discussed.     

Chelatometrie. V

Zusammenfassung Äthylendiamintetraessigsäure läßt sich bei p_H 3 mit Eisen(III)-chloridlösung gegen das dunkelbraune Zersetzungsprodukt von Bindschedlers Grün als Redoxindicator titrieren. Die Bestimmungsmethode ist für technische Äthylendiamintetraessigsäure-Produkte gut geeignet.Auch einige Kationen werden sich nach Umsetzung mit einem gemessenen Äthylendiamintetraessigsäure-Überschuß und dessen Rücktitration indirekt bestimmen lassen. Über eine Methode der Chrombestimmung wird später berichtet.Mitteilung IV dieser Reihe: P. Wehber ⁵.     

含钒(IV)和钒(V)的钨锗混合价杂多酸盐的合成及其结构表征

报道了含钒(IV)和钒(V)的钨锗混合价杂多酸盐的合成、电子吸收光谱及单电子还原态的ESR谱。α-和β-[HGeV^I^VV2^VW9O40]^7^-的溶液ESR谱是由40余条超精细线组成的, 表明在阴离子中3个VO6八面体是角顶共用, 且其中一个桥氧原子是质子化的。     

V. Gouverneur

?The biggest challenge facing scientists is finding a way to make clean energy. If I could have dinner with three famous scientists from history, they would be Marie Curie, Dmitri Mendeleev, and Henri Moissan. …?“ This and more about Véronique Gouverneur can be found on page 3559.

     

Coarse-grained V representability

The unsolved problem of determining which densities are ground state densities of an interacting electron system in some external potential is important to the foundations of density functional theory. A coarse-grained version of this ensemble V-representability problem is shown to be thoroughly tractable. Averaging the density of an interacting electron system over the cells of a regular partition of space produces a coarse-grained density. It is proved that every strictly positive coarse-grained density is coarse-grained ensemble V representable: there is a unique potential, constant over each cell of the partition, which has a ground state with the prescribed coarse-grained density. For a system confined to a box, the (coarse-grained) Lieb [Int. J. Quantum Chem. 24, 243 (1983)] functional is also shown to be Gateaux differentiable. All results extend to open systems.