scholarly journals Effects of H2O, pH, and oxidation state on the stability of Fe minerals on Mars

2005 ◽  
Vol 110 (E12) ◽  
Author(s):  
P. L. King ◽  
H. Y. McSween
Keyword(s):  
Oxidation State ◽  
The Stability

Regulating the stability of 2D crystal structures using an oxidation state-dependent molecular conformation

2006 ◽  
pp. 2320 ◽  
Author(s):  
Jonathan P. Hill ◽  
Yutaka Wakayama ◽  
Wolfgang Schmitt ◽  
Tohru Tsuruoka ◽  
Takashi Nakanishi ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Oxidation State ◽  
Molecular Conformation ◽  
State Dependent ◽  
The Stability

Pyrazine-imide complexes: reversible redox and MOF building blocks

2015 ◽  
Vol 44 (6) ◽  
pp. 2880-2892 ◽  
Author(s):  
Matthew G. Cowan ◽  
Reece G. Miller ◽  
Sally Brooker
Keyword(s):  
Oxidation State ◽  
Building Blocks ◽  
Redox Couple ◽  
Reversible Redox ◽  
The Stability

Stepwise exchange of pyrazine for pyridine, in three bis-heterocycle-based imide ligands, tunes the potential of the [MII/III(ligand)2]0/+ redox couple, increasing the stability of the MII oxidation state by about 0.1 V per exchange.

The Nature of the UC Double Bond: Pushing the Stability of High-Oxidation-State Uranium Carbenes to the Limit

2013 ◽  
Vol 19 (22) ◽  
pp. 7071-7083 ◽  
Author(s):  
Oliver J. Cooper ◽  
David P. Mills ◽  
Jonathan McMaster ◽  
Floriana Tuna ◽  
Eric. J. L. McInnes ◽  
...  
Keyword(s):  
Double Bond ◽  
Oxidation State ◽  
High Oxidation State ◽  
High Oxidation ◽  
The Stability

scholarly journals Genesis and stability of accessory phosphates in silicic magmatic rocks: a Western Carpathian case study

Mineralogia ◽  
2008 ◽  
Vol 39 (1-2) ◽  
pp. 53-66 ◽  
Author(s):  
Igor Broska ◽  
Igor Petrík
Keyword(s):  
Oxidation State ◽  
Physical Factors ◽  
Early Stages ◽  
Magma Composition ◽  
Magmatic Rocks ◽  
The Stability ◽  
Degree Of Differentiation

Genesis and stability of accessory phosphates in silicic magmatic rocks: a Western Carpathian case studyThe formation of accessory phosphates in granites reflects many chemical and physical factors, including magma composition, oxidation state, concentrations of volatiles and degree of differentiation. The geotectonic setting of granites can be judged from the distribution and character of their phosphates. Robust apatite crystallization is typical of the early magmatic crystallization of I-type granitoids, and of late magmatic stages when increased Ca activity may occur due to the release of anorthite from plagioclase. Although S-type granites also accumulate apatite in the early stages, increasing phosphorus in late differentiates is common due to their high ASI. The apatite from the S-types is enriched in Mn compared to that in I-type granites. A-type granites characteristically contain minor amounts of apatite due to low P concentrations in their magmas. Monazite is typical of S-type granites but it can also become stable in late I-type differentiates. Huttonite contents in monazite correlate roughly positively with temperature. The cheralite molecule seems to be highest in monazite from the most evolved granites enriched in B and F. Magmatic xenotime is common mainly in the S-type granites, but crystallization of secondary xenotime is not uncommon. The formation of the berlinite molecule in feldspars in peraluminous melts may suppress phosphate precipitation and lead to distributional inhomogeneities. Phosphate mobility commonly leads to the formation of phosphate veinlets in and outside granite bodies. The stability of phosphates in the superimposed, metamorphic processes is restricted. Both monazite-(Ce) and xenotime-(Y) are unstable during fluid-activated overprinting. REE accessories, especially monazite and allanite, show complex replacement patterns culminating in late allanite and epidote formation.

Dependency of f states in fluorite-type XO2 (X = Ce, Th, U) on the stability and electronic state of doped transition metals

2019 ◽  
Vol 21 (47) ◽  
pp. 25962-25975 ◽  
Author(s):  
Qian Ding ◽  
Ruizhi Qiu ◽  
Bingyun Ao
Keyword(s):  
Transition Metals ◽  
Electronic State ◽  
Oxidation State ◽  
Quantum Mechanical ◽  
Fluorite Type ◽  
The Stability

Transition metals (TMs) exhibit different quantum-mechanical oxidation state (OSqm) population when doped into fluorite-type CeO2, ThO2 and UO2.

scholarly journals Directed Silica Co-Deposition by Highly Oxidized Silver: Enhanced Stability and Versatility of Silver Oxynitrate

2019 ◽  
Vol 9 (23) ◽  
pp. 5236 ◽  
Author(s):  
Carla J. Spina ◽  
Roohee Ladhani ◽  
Carlie Goodall ◽  
Michelle Hay ◽  
Rod Precht
Keyword(s):  
Oxidation State ◽  
Aqueous Media ◽  
Ph Gradients ◽  
Long Term Stability ◽  
Organic Precursors ◽  
The Stability ◽  
Silicic Acids ◽  
Silver Compounds ◽  
By Products

Novel silver compounds in higher oxidation states, Ag (II) and Ag (III), have emerged as desirable alternatives to existing forms of antimicrobial silver compounds. Offering enhanced efficacy without sacrificing biocompatibility. Unique physiochemical characteristics associated with higher oxidation state silver confer desirable therapeutic traits. However, these same characteristics create challenges in terms of long-term stability and chemical compatibility with conventional biomedical materials. Core-shell methodologies, utilizing silica as a mesoporous or amorphous shell, have been adopted to enhance the stability of reactive active ingredients or cores. These methodologies commonly utilize controlled condensation of silicic acids in non-aqueous media by way of hydrolyzing alkyl silicates: the Stöber process or modified processes thereof. However, these strategies are not conducive to cores of higher oxidation state silver wherein hydroxyl organic precursors and by-products are incompatible with strong oxidizing agents. Addressing these challenges, we present a strategy herein for the preparation of a self-directed silver oxynitrate-silica, Ag7NO11:SiO2, framework. The method described utilizes pH gradients generated from the oxidation reaction of soluble silver, Ag (I), with a strong oxidizing agent/alkaline silicate media to facilitate spatial control over the protonation and subsequent condensation of silicic acid from aqueous solution. The resulting Ag7NO11:SiO2 framework confers enhanced long term and thermal stability to silver oxynitrate without impairing aqueous degradation profiles or subsequent antimicrobial and antibiofilm activities.

On the stability of Pu(III) at different pH under non-inert conditions

2006 ◽  
Vol 94 (9-11) ◽  
Author(s):  
Mattias Olsson
Keyword(s):  
Solvent Extraction ◽  
Oxidation State ◽  
Extraction Method ◽  
Pt Catalyst ◽  
Argon Gas ◽  
Solvent Extraction Method ◽  
The Stability ◽  
State Composition

A glove-box in contact with the lab atmosphere has been used in a test to see whether trivalent plutonium can be kept in this oxidation state at different pH. The box hosted a vessel of Pu(III) solution through which a hydrogen/argon gas mix was bubbled in the presence of a Pd/Pt catalyst. The results of solvent extractions and UV-Vis spectra for this system show that such conditions should not be considered sufficient to keep plutonium trivalent at a pH above two. The solvent extraction method was not found to affect the oxidation state composition of the samples.

Cell Interactions With Fibronectin-Coated Electrically Conducting Polypyrrole Thin Films

1993 ◽  
Vol 331 ◽  
Author(s):  
Joyce Y. Wong ◽  
Robert Langer ◽  
Donald E. Ingber
Keyword(s):  
Oxidation State ◽  
Aqueous Media ◽  
Aortic Endothelial Cells ◽  
Transparent Films ◽  
Electrically Conducting ◽  
Polypyrrole Films ◽  
Vis Spectroscopy ◽  
Electrically Conducting Polymers ◽  
The Stability ◽  
Charged Form

AbstractSurface properties of electrically conducting polymers, including charge-density and wettability, can be altered reversibly by oxidation or reduction. Thus, these materials are interesting systems on which to study the interactions of proteins and cells with surfaces. The properties of polypyrrole were studied in environments suitable for protein adsorption and cell culture. Optically transparent films of polypyrrole were synthesized, and the stability of the oxidized and reduced states in aqueous media were studied. UV/VIS spectroscopy, cyclic voltammetry, and spectroelectrochemistry measurements confirmed the oxidation state of the polymer films. The positively-charged form of polypyrrole could be changed to its neutral form by applying a constant potential (-0.5 V vs. Ag/AgCl reference). It was found that the shape of bovine aortic endothelial cells on fibronectin-coated polypyrrole films can be controlled by varying the oxidation state of the polypyrrole.

scholarly journals Synthesis, structure and properties of V(III,IV and V) complexes with ONO Schiff bases

2019 ◽  
Vol 4 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Janusz Szklarzewicz ◽  
Anna Jurowska ◽  
Agata Olszewska ◽  
Maciej Hodorowicz ◽  
Ryszard Gryboś ◽  
...  
Keyword(s):  
Oxidation State ◽  
Group Structure ◽  
Point Of View ◽  
Stacking Interactions ◽  
Structure And Properties ◽  
Metal Centre ◽  
Schiff Base Ligands ◽  
Insulin Mimetic ◽  
State Point ◽  
The Stability

The synthesis and physicochemical properties of vanadium(III,IV,V) complexes with Schiff base ligands based on 3,5-dibromo-4-methoxy-salicylaldehyde and phenylacetic hydrazide (H2L1), 5-chlorosalicylaldehyde and 4-hydroxybenzhydrazide (H2L2) and 5-chlorosalicylaldehyde and 2-hydroxybenzhydrazide (H2L3) were presented. The formulas of the complexes {[V(L1)(HL1)]·EtOH (1), [VO(L2)(phen)]·2H2O (2) and [VO(L3)(EtO)] (3)} were proposed based on the elemental analysis, IR and UV-Vis spectra. Additionally, the IR and UV-Vis spectra (in solvents as well as in a solid state) have been discussed from the vanadium oxidation state point of view. The single crystal structure of 3 shows triclinic, P-1 space group, structure is stabilized by hydrogen bonds and strong π-π stacking interactions. The oxidation state of the metal centre was also confirmed by the magnetic susceptibility measurements. The stability of the complexes was measured in pH = 7.00 and in pH = 2.00 which allows to evaluate the use of these compounds as insulin mimetic compounds.

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