Solid oxides structures

The value of this standard potential is slightly modified depending on the solid oxide structure and reaches —0.857 V for the quartz structure. In most acidic or neutral solutions, this silicon oxide forms a protecting layer. However, when the solution pH is increased, the oxide will give rise to various sparingly soluble compounds due to the following dissociahon reactions ... 

The structure of these solid compounds is not known with certainty but an approximate formula might be NaAlOj.xHjO. Many aluminates occur in minerals, for example the spinels of general formula M (A102)2 where M may be Mg, Zn or Fe these have a mixed oxide structure, i.e. consist essentially of M AF and O ions. 

Red lead is insoluble in water. Like lead(II) oxide it can readily be reduced to lead. The structure of the solid, as the systematic name suggests, consists of two interpenetrating oxide structures, in which each Pb atom is surrounded octahedrally by six oxygen atoms, and each Pb" by three (pyramidal) oxygen atoms, the oxygen atoms being shared between these two units of structure. With dilute nitric acid the lead(ll) part dissolves, and the lead(IV) part precipitates as lead(IV) oxide ... 

An effect which is frequently encountered in oxide catalysts is that of promoters on the activity. An example of this is the small addition of lidrium oxide, Li20 which promotes, or increases, the catalytic activity of dre alkaline earth oxide BaO. Although little is known about the exact role of lithium on the surface structure of BaO, it would seem plausible that this effect is due to the introduction of more oxygen vacancies on the surface. This effect is well known in the chemistry of solid oxides. For example, the addition of lithium oxide to nickel oxide, in which a solid solution is formed, causes an increase in the concentration of dre major point defect which is the Ni + ion. Since the valency of dre cation in dre alkaline earth oxides can only take the value two the incorporation of lithium oxide in solid solution can only lead to oxygen vacaircy formation. Schematic equations for the two processes are... 

Earlier studies of 4-aminopyridine 1-oxide were less conclusive. The solid-state infrared spectrum could be interpreted to indicate the existence of both the imino structure and/or, more probably, the amino structure. Comparison of the actual pKa value of 4-aminopyridine 1-oxide wdth the value calculated using the Hammett equation was considered to indicate that the compound existed as such or as an equilibrium mixture with l-hydroxypyrid-4-onimine, the latter possibility being considered the less likely on the basis of resonance and bond energies/ Resonance energy and ultraviolet spectral considerations have been advanced to support the 4-aminopyridine 1-oxide structure/ The presence of an infrared absorption band at... 

The tape-casting method makes possible the fabrication of films in the region of several hundred micrometers thick. The mechanical strength allows the use of such a solid electrolyte as the structural element for devices such as the high-temperature solid oxide fuel cell in which zirconia-based solid electrolytes are employed both as electrolyte and as mechanical separator of the electrodes. 

PdF4 is the only stable palladium(IV) halide [18] (testimony to the oxidizing nature of palladium(IV)) and is a very moisture-sensitive diamagnetic red solid the structure is based on Pd6F24 hexameric units linked three-dimensionally. It has octahedrally coordinated palladium with two terminal (cis) fluorines and four bridging ones. Despite the absence of other tetra-halides, the complete series of PdX - exist (cf. Ir). 

N. E. Cohen, 13th Symp (Int) Combust (Proc) (1970), 1019—29 CA 76, 61471 (1972) To analyze and explain the mechanism of combustion of powdered metals in contact with a solid oxidizer (AP) with the powdered metal dispersed in solid AP (I), the combustion of various compressed I-Al and I-Mg mixts in N2 under various conditions in a high-pressure window bomb was studied. The regression-rate laws of the mixts at high and low pressures, the pressure limits for deflagration, and the structures of the combustion zone and of the surface were detd. The burning rate of various I-Al mixts, as a function of pressure, I particle size, and mixt ratio was determined by cinematography. The combustion was difficult to achieve... 

Over the last few years, we have made a number of novel discoveries using reactive salt fluxes in the crystal growth experiment of mixed-metal oxides. The most important outcome that these salt-inclusion solids have demonstrated is the propensity for structure- directing effects of the employed salt. These hybrid solids have revealed fascinating solid-state structures ranging from nanoclusters to three-dimensional open frameworks of current interest. Solids featuring mag-... 

Dicyanofuroxan (3,4-dicyano-l,2,5-oxadiazole 2-oxide), the precursor to the NCCNO (see structure 11) species, has been studied in the solid and gas phases to obtain both structural and electronic information. The solid-state structure determined by X-ray diffraction gives an orthorhombic space group PnaZ, with a= 10.2578(14), b = 10.8818(12), and c= 10.2259(15) A. There are two independent molecules with similar geometries in the asymmetric unit. The gas-phase molecule was characterized by Hel photoelectron, Hel and HLtti(3i7 photoionization, and IR spectroscopy. The... 

On further oxidation of Te62+ the next species that was isolated is the prismshaped Te64+ ion found in the solid-state structures of Tcv,[AsF6]4(S02)251 52 and (Te6)(Se8)[AsF6]6(S02)53 (Figure 11). 

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