Cobalt silicon containing

A few clusters of interest containing germanium and transition metals have been reported.136-138 Dimethylgermane was found to replace only the bridging carbonyls between cobalt in a mixed germanium/cobalt/iron cluster complex (Equation (107)), and replacement of the carbonyl bridging the iron metal centers was not observed.137 A similar reaction leads to replacement of a bridging carbonyl in a mixed cobalt/silicon cluster (Equation (108)).136... 

Alloys are metallic substances containing two or more elements which are miscible when molten and do not separate when solidified. They may be liquid or solid. This mixture of elements, usually but not necessarily metals, allows careful manipulation of strength, melting point, corrosion resistance, magnetic, thermal, electrical, and other properties steel, for example, is an alloy of iron and carbon often present with nickel, chromium, copper, aluminium, boron, tungsten, manganese, cobalt, silicon, and other elements. 

As has already been mentioned, divinyl silicon derivatives, similarly to monovinyl-substituted silicon compounds, are also completely inert to productive homometathesis, particularly as far as acyclic diene metathesis (ADMET) polymerization is concerned. However, we have shown in earlier reports that in the presence of ruthenium, rhodium and cobalt complexes containing or generating M-H and/or M-Si bonds, divinyl-substituted silicon compounds undergo de-ethenated (poly)condensation to yield a mixture of oligomers and cyclic unsaturated siloxanes, silazanes and caibosilanes, as shown in Scheme 2 [21-29]. 

The electrosynthesis of metalloporphyrins which contain a metal-carbon a-bond is reviewed in this paper. The electron transfer mechanisms of a-bonded rhodium, cobalt, germanium, and silicon porphyrin complexes were also determined on the basis of voltammetric measurements and controlled-potential electrooxidation/reduction. The four described electrochemical systems demonstrate the versatility and selectivity of electrochemical methods for the synthesis and characterization of metal-carbon o-bonded metalloporphyrins. The reactions between rhodium and cobalt metalloporphyrins and the commonly used CH2CI2 is also discussed. 

Miller (90), King (209, 210), and Bruce (211) first observed the formation of neutral metal fluoride species and metal fluoride-containing ions in the mass spectra of pentafluorophenyl derivatives of phosphorus, germanium, silicon, and phosphido-bridged iron carbonyls (90) and aliphatic and aromatic fluorocarbon derivatives of iron, cobalt (209-211),... 

Recently, MCM-9 (ref. 9) has been shown to be a mixture of Si-VPI-5 and SAPO-11 (refs. 10-12). However, it is not clear what the framework silicon concentrations are in either Si-VPI-5 (ref. 5) or MCM-9 (ref. 12). If one assumes the maximum levels of substitution from bulk chemical analysis, the silicon concentrations are low. Low element substitution was shown to be true for Co-VPI-5 (cobalt containing VPI-5) (ref. 5) as well. 

Assay of beryllium metal and beryllium compounds is usually accomplished by titration. The sample is dissolved in sulfuric acid. Solution pH is adjusted to 8.5 using sodium hydroxide. The beryllium hydroxide precipitate is redissolved by addition of excess sodium fluoride. Liberated hydroxide is titrated with sulfuric acid. The beryllium content of the sample is calculated from the titration volume. Standards containing known beryllium concentrations must be analyzed along with the samples, as complexation of beryllium by fluoride is not quantitative. Titration rate and hold times are critical therefore use of an automatic titrator is recommended. Other fluoride-complexing elements such as aluminum, silicon, zirconium, hafnium, uranium, thorium, and rare earth elements must be absent, or must be corrected for if present in small amounts. Copper—beryllium and nickel—beryllium alloys can be analyzed by titration if the beryllium is first separated from copper, nickel, and cobalt by ammonium hydroxide precipitation (15,16). 

These alloys are available as wrought or cast alloys. The principal wrought copper alloys are the brasses, leaded brasses, phosphor bronzes, aluminum bronzes, silicon bronzes, bciylhum coppers, cupronickels. and nickel silvers. The major cast copper alloys include the red and yellow brasses, manganese, tin, aluminum, and silicon bronzes, beryllium coppers, and nickel silvers. The chemical compositions range widely. For example, a leaded brass will contain 60% copper, 36 to 40% zinc, and lead up to 4% a beryllium copper is nearly all copper, containing 2.1% beryllium, 0.5% cobalt, or nickel, or in another formulation, 0.65% beryllium, and 2.5% cobalt. 

Heanes [97] has described a method for determining copper, manganese and zinc in ashed plant extracts by flame AA spectrophotometry after cobalt and molybdenum have been assayed on separate aliquots of the same plant extracts by a spectrophotometric procedure [102]. (See Sect. 7.34.3). Ashing aids were necessary to maintain accuracy in the determinations. Concentrations of up to 3.5% m/m of silicon and calcium and 4% m/m of chlorine in the plants did not affect the determinations, but in some instances lower concentrations were determined in plant samples containing equal or higher levels of both added silica and calcium. 

In several other cases, compounds have been synthesized that contain potentially reactive groups attached to silicon, although their functionality has not yet been exploited. These include the methyl-chlorosilyl cobalt derivatives Cl Me3-nSiCo(CO)4 (re = 1,2) (215) and platinum complexes such as fra/is-lEtaPIsPtCXISiHjPISiHals (168) (cf. Table VI, entries 8-10). 

In the presence of ruthenium, rhodium and cobalt complexes that initially contain or generate M-H and M-Si bonds, the divinylderivatives of silicon com-... 

Again the ease of reaction depends very much on Q (P, As) and the substituents R1 and R63, 64l The preparation of a compound containing an optically active silicon center, trans-(+)-Pt(Pme2ph)2Cl[Si meph(l-naphthyl)], showed that these complexes are formed with retention of configuration at the silicon96. The stereochemical characteristics are also retained in the syntheses of cobalt carbonyls according to Eq. (9)210 ... 

Silicon forms a variety of compounds containing clusters of transition metal atoms that exhibit a wide range of structures. DisUane reacts with Co2(CO)g to give the cobalt cluster (38) in which the silicon is coordinated to five Co atoms (equation 48). The Si-- Si distance of 2.817 A is too long for a bond (normally about 2.35 A) and the Si-Co distances average 2.336 A. ... 

In general, the catalysts contain varying quantities of the oxides of aluminum, potassium, calcium, magnesium, and silicon as promoters. Patents recommend adding sodium [243], beryllium [244], vanadium [245], uranium [246], or platinum [247]. Reference [248] describes cesium-containing catalysts. Catalysts patented by Lummus [249] and Ammonia Casale [250] contain cerium as additional promoter. ICI [251] has developed a cobalt-containing catalyst, as has Grande Paroisse [252]. 

The term steel actually refers to a wide variety of products. The various forms of steel all contain iron and carbon. They also contain one or more other elements, such as silicon, titanium, vanadium, chromium, manganese, cobalt, nickel, zirconium, molybdenum, and tungsten. Two other steel-like products are cast iron and wrought iron. Cast... 

Fig. 5 (A) Polarization curve of an electrolyte containing cobalt sulfate, (B) scanning electron microscope (SEM) image of a Co deposit obtained at —1.1 V, and (C) the corresponding deposition current as a function of time (current transient). The reference electrode was saturated calomel and the working electrode semiconducting silicon. (From Ref...

---