Oxides of alkali metals

CI2 into alkaline solutions of Br ). lodates can be prepared either by direct high-pressure oxidation of alkali metal iodides with oxygen at 600° or by oxidation of I2 with chlorates ... 

In the case of oxides of alkali metals, the basic sites able to abstract protons from a reactant molecule are those associated with ion pairs and OH groups,... 

Ternary and polynary oxides of trivalent to hexavalent americium are obtained by solid-state reactions of Am20s and Am02 with the oxides of various elements. Compounds of pentavalent and hexavalent americium, which are iso-structural with the corresponding ternary oxides of Pa, U, Np, and Pu, are formed only with the oxides of alkali metals and alkaline earth metals. By reaction of Am02 with oxides of tetravalent elements—e.g., SiO, ZrO, or... 

In a review of the mechanisms of homogeneous reductions of inorganic species by tetrahydroborates, Hanzlik was able to compare the mechanism of the redox process proper with the homo- and hetero-geneous oxidation of alkali-metal tetrahydroborates.30... 

Davis and coworkers have shown that A -sulfonyl oxaziridines are potent oxidants [741], In order to induce asymmetry, these authors prepared rigid, bulky oxaziridines bearing the bomane skeleton. Oxaziridines 2.82 (X = H, Cl or Me) are very interesting reagents for the asymmetric oxidation of alkali metal enolates to a-hydroxyketones [147, 742-746], In some cases, the presence of chlorine or methoxy substituents on reagents 2.82 is necessary to observe a high asymmetric induction [747, 748], Both enantiomers are available, and these chiral reagents may be recycled. 

A-composition curves for all the studied oxides of alkali metals are practically coincident, and their acidic properties are comparable with those of NaP03 melt (Fig. 1.2.2, point 7). At the same time, at lower molar fractions of B203 the A values differ appreciably, and increase in the following sequence of cations Li+-Na+-K+. 

As mentioned above, this substance is more stable in long-term storage than are the oxides of alkali metals. Reference data show that heating pure Na202 to temperatures above 460 °C results in its decomposition to sodium oxide [114, 121]. Dissolution of Na202 in molten salts leads to decomposition at appreciably lower temperatures. Nevertheless, in molten nitrates possessing... 

In the present work the behaviour of zirconia samples doped with oxides of alkali metals and alkaline-earth metals was investigated, in order to better understand the role of both the nature and the amount of the doping cation. Li-, K-, Ca-, and Ba-doped zirconia samples were prepared. Their surface acid-base properties were assessed by means of adsorption microcalorimetry, using ammonia and carbon dioxide as probe molecules. Their catalytic activity for the 4-methylpentan-2-ol dehydration was tested in a flow microreactor. 

However, since the alkaline earth metal oxides in particular are comparatively stable, molecular bands, arising from metal oxides or hydroxides, are frequently observed in the spectra of these elements. In contrast to this, the oxides of alkali metals are less stable, resulting in strong atomic lines. 

Chemical reactions by contact with water may have various mechanisms. Hydrolysis, oxidation of alkali metals or simple decomposition of the substance, can be involved. It can also be a reaction of hydration for anhydride prodncts. Corrosivity of chemicals reacting with water will be mainly linked to two factors the temperature released in an exothermic reaction and/or the nature of the molecules released at the end of the reaction (e.g hydrochloric acid - HCl). 

According to [99], the formation of active intermediate metal-containing particles within i fuel-deficient flame occurs as a result of the direct oxidation of alkali metals, and the metal superoxide is formed ... 

The formation of rare earth silicates can be accelerated by the addition of flux material to the reaction mixture. The accelerators may be halides, carbonates, sulfates or oxides of alkali metals, earth alkaline metals, lead, zinc, bismuth, etc. (Leskela and Niskavaara, 1981). The amount of the accelerator represents only a few percent of the total weight of the reaction mixture. For example, using alkah fluorides it is possible to reach a complete conversion to silicate in the temperature range 1000-1300°C (Watanabe and Nishimura, 1978 Leskela and Niskavaara, 1981). 

In addition to the binary oxides of the actinides there are many compounds that are made by reaction of these with oxides of alkali metals, transition metals, alkaline earths, and some other elements. Comprehensive surveys of these by Keller [38] and Morss [540] provide lists of known compounds and organize the available crystallographic data to show the isostructural series that exist. They... 

Furthermore, the dependence of the molar volume on the composition for oxides of alkali metals and other metals forming M2O oxides and also for alkaline earth metal oxides, is presented in Fig. 3 and for group 11-15 oxides is depicted in Fig. 4. 

Oxidation of alkali metal sulfites to sulfates occurs to some extrat in all alkali metal-based SO2 absorption processes that treat flue gases containing free oxygra. As previously noted, about 20% of the nonregenerable sodium hydroxide/carbonate-based plants in Japan continue the oxidation to essentially 100% sodium sulfrite by bubbling air through the solution. 

The oxygen pressure at which the oxides of the metals Co, Fe(II), Zn, Mn, Mg, Na, K, Ca, Li, Ba(II) are still stable at 600 °C is very small [19] (< 10 atm). Hence, the important factor is the solubility of the oxide in the melt. The PCO2 values at which the oxides of alkali metals and barium precipitate from the melt are positive and large. Carbonates with these cations display good thermal stability while considerable pressures of carbon dioxide are required to guarantee stability for the other carbonates at 600 °C. Acid-base considerations make it also understandable [19] that the basic oxides have excellent properties as container material for carbonates. 

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