Suboxide determinations

Lower Oxides. A number of hard, refractory suboxides have been prepared either as by-products of elemental boron production (1) or by the reaction of boron and boric acid at high temperatures and pressures (39). It appears that the various oxides represented as B O, B O, B22O2, and B23O2 may all be the same material ia varying degrees of purity. A representative crystalline substance was determined to be rhombohedral boron suboxide, B12O2, usually mixed with traces of boron or B2O3 (39). A study has been made of the mechanical properties of this material, which exhibits a hardness... 

Suboxides exist for the larger alkali metals. The crystal structures of all binary suboxides (except CS3O) as well as the structures of CsnOsRb, Csn03Rb2, and Csn03Rb7 have been determined by single-crystal X-ray analysis. The structural data are listed in Table 12.2.2. All structures conform to the following rules ... 

In situ techniques have allowed simultaneous measurement of catalytic and spectroscopic data (463, 468), estabhshing the morphology and electronic structure of the working catalyst under dynamic conditions. Copper suboxide was found to be the catalytically active phase, which represents a metastable state in UHV or under ambient conditions. This result suggests that the structure of the catalyst under reaction conditions can be significantly different from that determined after reaction or under ex situ conditions. 

Uhlir (7) suggested that die thick anode film which forms on silicon in aqueous HP solutions below the critical current density is a suboxide of silicon. Faust (27) and Wang (30) also assumed it to be some kind of oxide layer. On the basis of experimental results which indicated that die critical current density was determined by the rate of mass transfer of HP to the silicon, Turner (29) presumed the anode film to be (SiF 2)x ... 

X-ray emission spectra and atomic site determination Boron suboxide The second successful example of the... 

Carbon suboxide C3O2 has been the subject of several papers. Earlier workers . disagreed as to whether the structure is linear or bent. A (9,5,I)->[4,3,1] basis set calculation concluded that it is essential to include f/-orbitals to determine the potential for CCC bending. Although the agreement with experiment was not satisfactory, the molecule is predicted to be non-linear but it was concluded that a more extensive basis set calculation is needed. Calculations including Cl are needed here. 

A sample of a suboxide of cesium gives up 1.6907% of its mass as gaseous oxygen when gently heated, leaving pure cesium behind. Determine the empirical formula of this binary compound. 

Diels, Otto P. H. (1876-1954). A German chemist who won a Nobel Prize in chemistry with Alder in 1950. He was awarded the prize for diene synthesis work which led to improved methods of analyzing and synthesizing organic compounds. His research resulted in the discovery of carbon suboxide, methods of dehydrating cyclical hydrocarbons using selenium, and determination of the structure of steroids. A student of Fischer s, Diels graduated from the University of Berlin. 

The oxide formation according to this two-step process is consistent with the thermodynamics. In the corresponding Pourbaix diagram, stable NbO and Nb02 modifications exist between Nb and Nb205. The formation of the suboxide in the first step can not be seen in the capacitance measurements due to its conductivity. Therefore, a more anodic oxide formation potential Uox is determined from the reciprocal capacitance curve. However, the slope of the curve used for determination... 

Meanwhile, the study to determine suboxides of phosphorus proceeded. It is well known that the phosphate ion reacts with molybdate ion to form a yellow phosphomolybdate salt and that this salt produces a blue solution in the presence of a reducing agent. Samples of known compounds containing phosphate ion readily and quickly form this blue solution, whereas samples containing phosphite ion do not react positively unless oxidized first to phosphate ion. 

Table 4. Plasma frequencies determined from reflectivity data for Cs and some suboxides. (63) In the case of the cluster compounds CS7O and CS11O3 the agreement between experimental (no) and expected numbers of free electrons (nc) is convincing. A large deviation is found for CS3O . The small value of no most probably reflects an enrichment of Cs at the phase boundary between the sample and the glass...

XPS (ESCA) and UPS are powerful tools to determine electronic energy levels by irradiating a sample with monochromatic X-rays and UV light, respectively, and measuring the energy distribution of the emitted electrons. With alkali metal suboxides UPS provides a quantitative proof of the bond model. Furthermore, the UPS results offer an explanation for the low energy photoemission process with oxidized Cs and thus (unexpectedly) open up a field of applied research with infrared sensitive photocathodes. The discussion of the results will be focussed on the chemical bonding. 

Assuming a free electron-like behavior of the valence electrons remaining at the alkali metal atoms in the suboxides, the experimentally determined width of the conduction band provides a measure for the electron density and thus a proof of the bond model. 

In this study, suboxides of vanadia catalysts were used in pentane, pentene, dicyclopentadiene and cyclopentane oxidation reactions. In the previous phase of the work [12,13], the role of alkali promoters on the catalyst selectivity was examined. The catalysts were reduced in situ at different temperatures and the effect of pre-reduction temperature was investigated. Controlled-atmosphere characterization of pre-reduction, post-reduction, and post-reaction catalysts were performed using X-ray diffraction. X-ray photoelectron spectroscopy, laser Raman spectroscopy and temperature-programmed desorption experiments. The objectives of this study were to determine the activity and selectivity of different suboxides of vanadia in... 

CO laser probing of the vibratiopally excited CO formed in combustion-related reactions has proved valuable in gaining an understanding of the course of these reactions. Much useful data have been obtained pertinent to the determination of reaction mechanisms and the identity of intermediates taking part in the reactions. A number of reactions of O P) with allene, alkynes, carbon suboxide, and some free radicals are described below. 

UPS [He (I)] data for the suboxides CsnOj, [CsnOaJCsio, and [Csn03]Rb7 have been determined at 98 5K7 Extremely narrow oxygen 2p levels are observed (Table 4) as well as significant differences in the binding energies of the 5p levels of chemically different Cs atoms. The results are rationalized in terms of the structurally derived bonding models discussed above... 

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