Same-metal oxide

Many of these oxoanions can form, depending on concentration and pH, various surface complexes. This ability may explain the different effects observed under different solution conditions. For example, Bondietti et al. (33) found that phosphate at low pH (where mononuclear complexes are probably formed) accelerated EDTA-promoted dissolution of lepidocrocite, whereas at near-neutral pH conditions (where binuclear complexes are presumably formed), phosphate was an efficient inhibitor. Furthermore, because of the several geometries involved, the extent of comer sharing or edge sharing by adsorbed oxoanions may differ with the type of oxide and with allotropic modifications of the same metal oxide. 

The purposes of this experiment are to study some of the properties of HNO3, NO3 , and NO2 , and to prepare and study some properties and reactions of several oxides of nitrogen. In addition, you will prepare a metal oxide by oxidation of an unknown metal with HNO3, and you will prepare the same metal oxide by thermal decomposition of a nitrate salt. From your mass data you will determine the empirical formula of the metal oxide, the atomic mass of the metal, and thus the unknown metal that you have used. 

MODIFICATION OF OXIDES IN METAL-SAME-METAL OXIDE-lnP DEVICES... 

Same-metal oxides of materials are not normally used in MOS devices, due to their heterogeneity and nonstoichiometry (chemical composition depends significantly on the conditions of both production and snbsequent thermal treatment [49-51]). Therefore, at present, preference is given to MOS structures containing silicon oxides. Examples of such systems include Si02 on substrates made of GaAs, InP, and InSb, which were studied by IR absorption [52-54]. Nevertheless, MOS structures with same-metal oxides A B are still considered to be promising for a number of applications in optoelectronics, such as solar cells [1]. 

The influence of the deposition of metallic coatings and the thermal treatment on the structural and chemical properties of same-metal oxides formed on... 

In spectra of InP oxides between 2900 and 3500 cm and at 1650 cm , one can distinguish absorption peaks of the stretching and bending vibrations of the O—H groups these are most pronounced for the anodic oxide, considerably weaker for the chemical oxide, and practically absent for the thermal oxide and disappear upon slight thermal heating T 200-300°C) (Fig. 6.13 [55]). From this, it can be concluded that these peaks result from O—H groups of adsorbed water. Same-metal oxides do not contain detectable amounts of hydroxyl ion salts in the form In(OH)3 (the probability of their formation upon oxidation of InP in water solutions has been discussed [49]). 

Low-temperature annealing T = 300°C) causes the absorption spectra of anodic and chemical oxides to undergo substantial changes, namely an increase in the 940- and 1220-cm absorption peak intensities by a factor of 1.3-2.0. Thus, annealing results not only in the dehydration of same-metal oxides but also in an increase in the concentrations of P2O5 and InP04, which occurs in the oxide simultaneously with a decrease in the Iu203 concentration [55]. It is these latter effects that allow for the optimization of the electrophysical characteristics of MOS devices. 

TCO thin films can exhibit tremendous variability in transparency, microstructure (and surface roughness), surface composition, conductivity, chemical stability at high current densities (in OLEDs, OPVs, and chemical sensors), and in their chemical compatibihty with contacting organic layers. Variability is often noticeable from production batch to production batch and within batches of the same metal oxide material [34]. Surface pretreatment conditions have also been shown to dramatically impact the electrochemical, physical, and photophysical properties of metal oxide films [8, 9, 24, 26, 27, 35]. Modification... 

Let us first look at the reactions of reduction of the same metal oxide MO, by hydrogen on the one hand, and by carbon monoxide on the other. 

Although catalytic hydration of ethylene oxide to maximize ethylene glycol production has been studied by a number of companies with numerous materials patented as catalysts, there has been no reported industrial manufacture of ethylene glycol via catalytic ethylene oxide hydrolysis. Studied catalysts include sulfonic acids, carboxyUc acids and salts, cation-exchange resins, acidic zeoHtes, haUdes, anion-exchange resins, metals, metal oxides, and metal salts (21—26). Carbon dioxide as a cocatalyst with many of the same materials has also received extensive study. 

Metal oxide electrodes have been coated with a monolayer of this same diaminosilane (Table 3, No. 5) by contacting the electrodes with a benzene solution of the silane at room temperature (30). Electroactive moieties attached to such silane-treated electrodes undergo electron-transfer reactions with the underlying metal oxide (31). Dye molecules attached to sdylated electrodes absorb light coincident with the absorption spectmm of the dye, which is a first step toward simple production of photoelectrochemical devices (32) (see Photovoltaic cells). 

When the Diels-Alder reaction between butadiene and itself is carried out in the presence of alkah metal hydroxide or carbonate (such as KOH, Na2C02, and K CO on alumina or magnesia supports) dehydrogenation of the product, vinylcyclohexene, to ethylben2ene can occur at the same time (134). The same reaction can take place on simple metal oxides like Zr02, MgO, CaO, SrO, and BaO (135). 

Carburization by Thermal Diffusion. Carburization of chemically processed metal or metal-compound powders is carried out through sohd-state, thermal diffusion processes, either in protective gas or vacuum. Carbide soHd solutions are prepared by the same methods. Most carbides are made by these processes, using loose or compacted mixtures of carbon and metal or metal-oxide powders. HaUdes of Group 5 (VB) metals recovered from ores by chlorination are similarly carburized. 

Hydration of Ethyl Ether. Using the same type of acid catalysts as in the hydration of ethylene to ethanol, ethyl ether can be hydrated to the alcohol. Catalysts that have been used for the hydration of ether include phosphoric acid (144), sulfuric acid (145,146), hydrochloric acid (147), metallic oxides (141,148,149) and sihcates (150). Sulfuric acid concentrations ranging from 5—25% at 200°C (144) to 63—70% at 110—135°C and 1.01—1.42 MPa (10—14 atm) (148) have been claimed. 

Underdeposit corrosion is not so much a single corrosion mechanism as it is a generic description of wastage beneath deposits. Attack may appear much the same beneath silt, precipitates, metal oxides, and debris. Differential oxygen concentration cell corrosion may appear much the same beneath all kinds of deposits. However, when deposits tend to directly interact with metal surfaces, attack is easier to recognize. 

In the face-centred cubic structure tirere are four atoms per unit cell, 8x1/8 cube corners and 6x1/2 face centres. There are also four octahedral holes, one body centre and 12 x 1 /4 on each cube edge. When all of the holes are filled the overall composition is thus 1 1, metal to interstitial. In the same metal structure there are eight cube corners where tetrahedral sites occur at the 1/4, 1/4, 1/4 positions. When these are all filled there is a 1 2 metal to interstititial ratio. The transition metals can therefore form monocarbides, niU ides and oxides with the octahedrally coordinated interstitial atoms, and dihydrides with the tetrahedral coordination of the hydrogen atoms. 

Carbon and Hydrogen.—Carbon compounds are frequently inflammable, and when heated on platinum foil take fipe or char and burn away. A safer test is to heat the substance with some easily reducible metallic oxide, the oxygen of which forms carbon diovide with the carbon present. Take a piece of soft glass tube about 13 cm. (5 in.) long, and fuse it together at one end. Heat a gram or two of fine copper oxide in a porcelain crucible for a few minutes to drive off the moisture, and let it cool in a desiccator. Mix it with about one-tenth of its bulk of powdered sugar in a mortar. Pour the mixture into the tube, the open end of which is now drawn out into a wide capillary and oeni. at the same time into the form Fig. i. 

M2Ti04 (M = Mg, Zn, Mn, Fe, Co) have the spinel stmcture (MgAl204, p. 248) which is the third important stmcture type adopted by many mixed metal oxides in this the cations occupy both octahedral and tetrahedral sites in a cep array of oxide ions. Ba2Ti04, although having the same stoichiometry, is unique amongst titanates in that... 

The oxygen vacancies then diffuse to the gas interface where they are annihilated by reaction with adsorbed oxygen. The important point, however, is that metal is consumed and oxide formed in the same reaction zone. The oxide drift has thus only to accommodate the net volume difference between the metal and its equivalent amount of oxide. In theory this net volume change could represent an increase or a decrease in the volume of the system, but in practice all metal oxides in which anionic diffusion predominates have a lower metal density than that of the original metal. There is thus a net expansion and the oxide drift is away from the metal. 

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