Photooxidation of water by manganese(II) sulfate

The photoreduction of Mn(IV) sulfate in 6–10 M H₂SO₄ has been studied. The kinetics of the photoreaction are similar to that of the thermal oxidation of water by Mn(IV) sulfate. A strong dependence of the quantum yield on the energy of the absorbed quantum has been found. The mechanism of oxygen formation including decomposition of the “hot” dinuclear Mn complex is discussed.

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Изучена реакция фотовосстановления сульфата Mn(IV) в 6–10 М H₂SO₄ Показано, что кинетика изученной фотореакции идентична кинетике термической реакции окисления воды сульфатом Mn(IV). Обнаружена сильная зависимость квантового выхода от величины поглощенного кванта. Обсужден механизм формирования кислорода, включающий распад “горячего” биядерного комплекса марганца.

     

Observations on the hydrogen peroxide-iodic acid-manganese(II)-organic species oscillating system

The effect of acidity and manganese (II) concentration on the title reaction has been examined for acetone and malonic acid as the organic species. Cerium (III) has been shown to replace manganese (II) without loss of the oscillatory behavior. Some mechanistic details are given.

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Был исследован эффект кислотности и концентрации марганца (II) в заглавной реакции на примере ацетона и малоновой кислоты, как органических компонентов. Было обнаружено, что замена марганца (II) на церий (III) не приводит к исчезновению осциллирующего поведения. Приводятся некоторые детали механистической модели.

     

Solvolysis of (1-chloro-2,2-dimethylpropyl) benzene in presence and absence of mercury(II) chloride

The kinetics of solvolysis of the title compound has been studied in water and in 10 vol. % ethanol-water in the presence and absence of mercury (II) chloride. The results confirm the earlier conclusion that mercury(II) chloride is solvated in hydroxylic solvents.

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Кинетика сольволиза заглавного соединения была исследована в воде и в смеси этанола (10 об.%) с водой в присутствии и отсутствии хлористой ртути (II). Реэультаты подтверждают более раннее заключение, согласно которому хлористая ртуть (II) сольватируется в гидроксильных растворителях.

     

Atomic electron-pair distances and subshell radii in position and momentum space

For the 53 neutral atoms from He to Xe in their ground states, the average distances < u> _{n l , n ′ l ′} in position space and < v> _{n l , n ′ l ′} in momentum space between an electron in a subshell nl and another electron in a subshell n ^′ l ^′ are studied, where n and l are the principal and azimuthal quantum numbers of an atomic subshell, respectively. Analysis of 1700 subshell pairs shows that the electron-pair distances < u> _{n l , n ′ l ′} in position space have an empirical but very accurate linear correlation with a one-electron quantity U _{n l , n ′ l ′}≡L _r +S _r ²/(3L _r ), where L _r and S _r are the larger and smaller of subshell radii < r> _{n l} and < r> _{n ′ l ′}, respectively. The correlation coefficients are never smaller than 0.999 for the 66 different combinations of two subshells appearing in the 53 atoms. The same is also true in momentum space, and the electron-pair momentum distances < > _{n l , n ′ l ′} have an accurate linear correlation with a one-electron momentum quantity V _{n l , n ′ l ′}≡L _p +S _p ²/(3L _p ), where L _p and S _p are the larger and smaller of average subshell momenta < p> _{n l} and < p> _{n ′ l ′}, respectively. Trends in the proportionality constants between < u> _{n l , n ′ l ′} and U _{n l , n ′ l ′} and between < > _{n l , n ′ l ′} and V _{n l , n ′ l ′} are discussed based on a hydrogenic model for the subshell radial functions. Received: 8 April 1998 / Accepted: 6 July 1998 / Published online: 18 September 1998     

Interaction of phosphomolybdovanadium heteropolyacids with hydrazine hydrate studied by a calorimetric method

The heats of interaction of VO ₂ ⁺ and of heteropolyacids H_3+nPMo_12−nV_nO₄₀ (n=1,2,3,6) with N₂H₄ have been measured.

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Измерены теплоты взаимодействия VO ₂ ⁺ и гетерополикислот H_3+nPMo_12−nV_nO₄₀ (n=1,2,3,6) с N₂H₄.

     

Lanthantartrate im neutralen und alkalischen Bereich

Zusammenfassung Die Substanzen LaHT ^*·4 H₂O, La₄ T ₃·14 H₂O, KLaT· ·3 H₂O, K₂LaTOH·4 H₂O, K₂LaH₃ T ₂·4 H₂O, K₃LaH₂ T ₂· ·4 H₂O und K₄LaHT ₂·5 H₂O wurden isoliert und durch Thermoanalyse, IR-Absorptionspektren und Röntgenstreuung näher charakterisiert. Es wurde auch ihre Löslichkeit in Wasser bestimmt.

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The following compounds where isolated, and characterized by means of thermal analysis, I. R. spectroscopy and X-ray diffraction. Their solubilities in aqueous solution were determined: LaHT·4 H₂O, La₄ T ₃·14 H₂O, KLaT·3 H₂O, K₂LaTOH· ·4 H₂O, K₂LaH₃ T ₂·4 H₂O, K₃LaH₂ T ₂·4 H₂O, K₄LaHT ₂· ·5 H₂O.

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Mit 7 Abbildungen     

Thermal and X-ray diffraction analysis studies during the decomposition of ammonium uranyl nitrate

Two types of ammonium uranyl nitrate (NH₄)₂UO₂(NO₃)₄·2H₂O and NH₄UO₂(NO₃)₃, were thermally decomposed and reduced in a TG-DTA unit in nitrogen, air, and hydrogen atmospheres. Various intermediate phases produced by the thermal decomposition and reduction process were investigated by an X-ray diffraction analysis and a TG/DTA analysis. Both (NH₄)₂UO₂(NO₃)₄·2H₂O and NH₄UO₂(NO₃)₃ decomposed to amorphous UO₃ regardless of the atmosphere used. The amorphous UO₃ from (NH₄)₂UO₂(NO₃)₄·2H₂O was crystallized to γ-UO₃ regardless of the atmosphere used without a change in weight. The amorphous UO₃ obtained from decomposition of NH₄UO₂(NO₃)₃ was crystallized to α-UO₃ under a nitrogen and air atmosphere, and to β-UO₃ under a hydrogen atmosphere without a change in weight. Under each atmosphere, the reaction paths of (NH₄)₂UO₂(NO₃)₄·2H₂O and NH₄UO₂(NO₃)₃ were as follows: under a nitrogen atmosphere: (NH₄)₂UO₂(NO₃)₄·2H₂O → (NH₄)₂UO₂(NO₃)₄·H₂O → (NH₄)₂UO₂(NO₃)₄ → NH₄UO₂(NO₃)₃ → A-UO₃ → γ-UO₃ → U₃O₈, NH₄UO₂(NO₃)₃ → A-UO₃ → α-UO₃ → U₃O₈; under an air atmosphere: (NH₄)₂UO₂(NO₃)₄·2H₂O → (NH₄)₂UO₂(NO₃)₄·H₂O → (NH₄)₂UO₂(NO₃)₄ → NH₄UO₂(NO₃)₃ → A-UO₃ → γ-UO₃ → U₃O₈, NH₄UO₂(NO₃)₃ → A-UO₃ → α-UO₃ → U₃O₈; and under a hydrogen atmosphere: (NH₄)₂UO₂(NO₃)₄·2H₂O → (NH₄)₂UO₂(NO₃)₄·H₂O → (NH₄)₂UO₂(NO₃)₄ → NH₄UO₂(NO₃)₃ → A-UO₃ → γ-UO₃ → α-U₃O₈ → UO₂, NH₄ UO₂(NO₃)₃ → A-UO₃ → β-UO₃ → α-U₃O₈ → UO₂.     

Chemie der Seltenerdmetalle, 26. Mitt.: Tartrate der Seltenen Erden des TypsLn 4 T 3·xH2O und ihre Reaktion mit HCl

Zusammenfassung Nachstehende Verbindungen wurden hergestellt: Pr₄ T ₃·13 H₂O, Nd₄ T ₃·12 H₂O, Sm₄ T ₃·12 H₂O, Gd₄ T ₃·12 H₂O, Tb₄ T ₃·13 H₂O, Dy₄ T ₃·12 H₂O, Ho₄ T ₃·14 H₂O, Er₄ T ₃·14 H₂O, PrH₂ TCl·3 H₂O, NdH₂ TCl·3 H₂O, SmH₂ TCl·3 H₂O, GdH₂ TCl·4 H₂O, TbH₂ TCl·3 H₂O, DyH₂ TCl·2 H₂O, HoH₂ TCl·3 H₂O, ErH₂ TCl·3 H₂O. Die Präparate wurden mit Thermoanalyse, IR-Absorptionsspektren, Röntgenstreuung und hinsichtlich Löslichkeit weiter untersucht.

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Chemistry of the rare earth metals, XXVI: Tartrates of the rere earths of the types Ln₄T₃·xH ₂ O, and their reaction withHCl

The above series of compounds has been prepared and further characterized by thermal analysis, IR spectra, X-ray diffraction, and solubility.

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Ln=Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er.

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H₄ T=C₄H₆O₆.