Showing papers on "Oxidation state published in 1986"
TL;DR: In this paper, surface spectroscopy measurements of silicon single-crystal wafers which have been treated in order to obtain hydrophilic and hydrophobic surfaces, respectively, were reported.
Abstract: The paper reports on surface spectroscopy measurements of silicon single-crystal wafers which have been treated in order to obtain hydrophilic and hydrophobic surfaces, respectively. The wafers are characterized in terms of the oxidation behaviour in air (“native oxides”), their surface chemical composition and the chemical bonds involved. It is shown that the oxide on hydrophilic wafers mainly grows in the cleaning agent and consists of hydrated SiO2 through all stages of the growth. On a hydrophobic surface, however, the oxidation begins with the formation of a lower oxidation state which turns into SiO2 on storage in air. The thickness of the oxides on both surface types reaches 1.4–1.5 nm. Both the chemical shift in photoelectron spectroscopy and the frequency of the asymmetric Si-O-Si vibration in electron energy loss spectroscopy support the assumption of a reduced bonding angle of the oxygen bridge. Hydrophilicity is caused by singular and associated OH groups on the surface. Singular groups could be detected up to 700 K. There are hints that OH groups stabilize the oxide during heating. The hydrophobic state is mainly characterized by Si-H and Si-CH
x
groups on the surface, whereas Si-F exists only in minor quantities. Si-H groups were stable up to approximately 900 K in UHV. Si-CH
x
dehydrogenizes at temperatures between 500 and 700 K leaving SiC on the surface.
373 citations
TL;DR: In this article, high resolution Ge 3D photoelectron spectra obtained with synchrotron radiation are used to determine the surface oxidation states of Ge(100) and Ge(111) surfaces.
252 citations
221 citations
TL;DR: A detailed study of the thermal deactivation of a commercial Hopcalite catalyst, "CuMn2O4", has been made by a multitechnique catalyst characterization approach using XPS, ISS, XRD, SEM, TA, and activity testing as mentioned in this paper.
164 citations
TL;DR: In this article, the catalytic properties of spores of a marine Bacillus known to oxidize divalent manganese were used to perform laboratory Mn(II) oxidation experiments at environmental conditions of pH and Mn (II) concentration.
136 citations
TL;DR: X-ray photoelectron spectra of several Palladium fluorine compounds have been investigated in this article, and the results clearly confirm the unusual +III oxidation State of Palladium in NaPdF4, Na3pdF6, K3Pd F6, and K2NaPdrF6.
Abstract: X-ray photoelectron spectra of several Palladium fluorine compounds have been investigated. In all these phases Palladium atoms have a more or less distorted octahedral coordination. Satellite Structures generally occur in Pd 3d3/2 and Pd 3d5/2 levels and broad F 1s peaks are observed. Shifts in binding energies can be correlated with Palladium oxidation State and covalency. XPS results clearly confirm the unusual +III oxidation State of Palladium in NaPdF4, Na3PdF6, K3PdF6, and K2NaPdF6.
95 citations
TL;DR: The oxidation of Si(100) surfaces covered with 3 A Ce was studied by high-resolution photoemission spectroscopy and indicated the formation of a well-defined compound in which both Ce and Si are in a 3+ oxidation state.
Abstract: The oxidation of Si(100) surfaces covered with 3 A Ce was studied by high-resolution photoemission spectroscopy. The oxygen uptake was found to be enhanced by orders of magnitude by the presence of Ce. Because of chemical reaction between Ce and Si, a mixed oxide with a Ce:Si:O composition ratio of 1:1:3 is formed. The sharp photoemission spectra of this oxide indicate the formation of a well-defined compound in which both Ce and Si are in a 3+ oxidation state.
85 citations
TL;DR: In this paper, the NiCo2O4 catalyst has been characterized using cyclic voltammetric and rotating ringdisc electrodes to correlate the electrocatalytic activity and spinel structure.
66 citations
65 citations
TL;DR: In this article, an investigation of the cyclic voltammetry behavior of gold in aqueous sulphate media (pH = 11.7), containing dissolved organic or inorganic bases, confirmed the existence of reversible redox transitions at ca. 0 V (RHE).
50 citations
TL;DR: In this paper, high oxidation state tungsten-carbene complexes similar to W(CHt-Bu)(OCH2t-bu)2Br2 were synthesized and their physical and chemical properties analysed and compared.
TL;DR: In this article, a review of recent work on redox chemistry of Mo-S systems is presented, where both the Mo and S oxidation states change and the net reaction embodies an induced internal electron transfer from S to Mo in the same sense that Taube et al. elucidated in the chemistry of cobalt.
TL;DR: In this paper, the surface morphology of NiCo2O4 spinel oxide was characterized by a number of ex situ non-electrochemical techniques, including WB measurements and scanning electron microscopy X-Ray diffraction, temperature-programmed reduction (TPR) and X-ray and Auger photoelectron spectroscopy.
TL;DR: In this article, the titration Eredox against the mean state of oxidation of the solution and the absorption spectra of solutions with different mean states of oxidation were determined as E'12 = - 0.935, E'13 = -0.931 and E'14 = −0.8 2-.
Abstract: Spectrophotometric, titrimetric, electron spin resonance and 77Se nuclear magnetic resonance studies made on the alkaline selenide, selenium electrolyte showed that soluble selenium species existed in four oxidation states, none of the species was a radical, and the mean state of oxidation of the Se-saturated solution was equivalent to Se3.8 2-. It was concluded that the species were Sen 2- with n = 1, 2, 3 and 4, or their protonated forms. On the basis of the Nernst equation, we analysed independently (a) the titration Eredox against the mean state of oxidation of the solution and (b) the absorption spectra of solutions with different mean states of oxidation. Thus formal redox potentials E' were determined as E'12 = -0.935, E'13 = -0.931 and E'14 = -0.914 V against s.c.e. for the couples Se2-, Se2 2-, Se2-, Se3 2- and Se2-, Se4 2- respectively in 1 mol dm-3 KOH supporting electrolyte at 304 K. It followed that E'23 = -0.919 for Se2-, Se32- and E' = -0.778 for Se3 2-, Se4 2- The concentration of each species at each redox potential and the absorption spectrum of each distinct oxidation state were found. Excellent fits and agreement between the two analyses were observed. Ultraviolet absorption spectra showed that the reduced ion was approximately 50% protonated in 1 mol dm-3 KOH supporting electrolyte.
TL;DR: In this article, the electrochemical preparation and characterisation in terms of oxidation state, spectra, stability, and reduction potentials of IrIV and IrV aqua ions in 2 M HClO4, and related binuclear IrIII ions, are described.
Abstract: The electrochemical preparation and characterisation in terms of oxidation state, spectra, stability, and reduction potentials of IrIV and IrV aqua ions in 2 M HClO4, and related binuclear IrIII ions, is described.
TL;DR: In this paper, the results obtained from the adsorption of pyrrole on Fe- and Cu-exchanged Y zeolites were analyzed using In situ IR was the major tool used for monitoring the surface reactions.
TL;DR: In this article, a thermal treatment process was used to systematically reduce the Cr(+6) species to Cr(3)-containing species and a pulse technique was developed to non-destructively quantify this reduction using hydrogen.
TL;DR: Les complexes d'oxovanadium avec l'ethylene bis ([o-hydroxyphenyl] glycine), EHPG, sont isoles et caracterises comme contenant du vanadium (IV) and duvanadium (V) as mentioned in this paper.
Abstract: Les complexes d'oxovanadium avec l'ethylene bis ([o-hydroxyphenyl] glycine), EHPG, sont isoles et caracterises comme contenant du vanadium (IV) et du vanadium (V). Les etudes d'oxydoreduction electrochimique permettant d'etablir une relation entre ces 2 etats d'oxydation
TL;DR: In this article, the interaction between saccharose and manganese in different oxidation states was studied in alkaline media by polarographic, potentiometric, ESR spectroscopic and UV-Vis spectrophotometric methods.
TL;DR: In this paper, it was determined from spectroscopic and electrochemical studies that at least partial oxidation to the IV oxidation state of cerium occurred and that the lanthanides were oxidized to the 4 oxidation state.
Abstract: Cerium(III), praseodymium(III) and terbium(III) nitrates were subjected to prolonged (3–24 h) ozonolysis in the presence of oxygen donor ligands in acetonitrile at 70 °C in an effort to stabilize the IV oxidation state of these metal ions. From spectroscopic and electrochemical studies it was determined that the lanthanides were oxidized to the IV oxidation state. Acetonitrile solutions of cerium(III) nitrate and cerium(III) chloride in the presence of triphenylarsine oxide (TPAsO) were also subjected to prolonged bubbling with air or oxygen at 70 °C. It was determined from spectroscopic studies that at least partial oxidation to the IV oxidation state of cerium occurred.
TL;DR: In this paper, the conditions necessary for preparing the recently reported μ-oxo-ironhemiporphyrazinate compounds (Fe(IV)hpO) n and [(Fe(III)hp) 2 O]H 2 O are given.
TL;DR: In this article, the microstructure of polypentenamer resulting from cyclopentene polymerization initiated by two types of WCl 6 -based catalytic systems has been determined from the 13 C NMR spectrum.
TL;DR: The PI Complex (Ia) is reversibly oxidized by air, Na2S2O8, or Ce(IV) in a strongly acidic solution to form a platinum blue related diamagnetic complex (Ib) whose average metal oxidation state is 3.0 as mentioned in this paper.
Abstract: The PI Complex (Ia) is reversibly oxidized by air, Na2S2O8, or Ce(IV) in a strongly acidic solution to form a platinum blue related diamagnetic Complex (Ib) whose average metal oxidation state is 3.0.
TL;DR: In this paper, it was shown that the usual monotonic variation of the edge energy with oxidation state depends closely on the electrical properties of the material and on the symmetry of the iron site.
TL;DR: The electrolysis of trivalent californium, terbium, and praseodimium in 2M K2CO3 solutions at pH 13.2 results in partial oxidation of the trivalents ions to a higher oxidation state as discussed by the authors.
Abstract: The electrolysis of trivalent californium, terbium and praseodimium in 2M K2CO3 solutions at pH 13.2 results in a partial oxidation of the trivalent ions to a higher oxidation state. Absorption spectra of Cf/III/ in 1M HCLO4 and in 2M K2O3 and that of oxidized californium in carbonate solution have been recorded. Incomplete oxidation is accounted to a reducing species generated at high anode potentials.
TL;DR: In this paper, the redox behavior of the head-to-head bis(μ- (1-methyluracilato- N 3, O 2 )-bis( cis-diammine platinum(II)) dinitrate, PtMeU, and platinum 1-methyluranacil blue (PMeUB), PtMeUB, was studied by cyclic voltammetry (CV) and controlled-potential coulometry (CPC).