Calcium oxide, structure determination

The new silazane 5 may be reacted with activated metals, organometallic compounds or simple metal amides, or may first be transformed to its lithium salt and then reacted with metal(II) chlorides [11]. In all these cases, metal derivatives of 5 are obtained with the general formula j [Mc (/BuO)Si 9N(9M, which have no further base coordinated to the metal. So far we have synthesized amides with M = Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Ba, all elements in oxidation state +2. X-ray structure determinations have been performed on the calcium, manganese, iron, zinc, and barium derivatives. 

Given that strontium oxide crystallizes with the same structure as calcium oxide, use data tables to estimate the minimum cation/anion distance and hence determine the lattice energy for SrO. 

The reduction procedure involves treating the catalyst in the oxide state with a stoichiometric mixture of nitrogen and hydrogen. The temperature and extent to which this is carried out is dependent on the concentration of potassium, aluminum oxide, and particularly calcium oxide in the catalyst formation. About 1% to 3% of K2O and AI2O3 are usually used and, following reduction, somewhere between 40% and 60% of the iron surface is covered by the promoters. Previous work has determined that the presence of aluminum in the catalyst results in an increase of the surface area of the catalyst on reduction, from a value of 1 m per g cat for unpromoted iron to 20 m per g cat (so-called structural promotion). The presence of potassium decreases the surface area to about 10 m per g cat, but the overall activity of the catalyst increased by a factor between three and six (so-called electronic promotion). 

The ash content of furnace blacks is normally a few tenths of a percent but in some products may be as high as one percent. The chief sources of ash are the water used to quench the hot black from the reactors during manufacture and for wet pelletizing the black. The hardness of the water, and the amount used determines the ash content of the products. The ash consists principally of the salts and oxides of calcium, magnesium, and sodium and accounts for the basic pH (8—10) commonly found in furnace blacks. In some products potassium, in small amounts, is present in the ash content. Potassium salts are used in most carbon black manufacture to control structure and rubber vulcanizate modulus (22). The basic mineral salts and oxides have a slight accelerating effect on the vulcanization reaction in mbber. 

V(acac)3 has several applications, including its use as a component in olefin polymerization catalysts it is air sensitive, undergoing gradual oxidation in moist air to give VO(acac)2. Commercial V(acac)3 is allowed to contain not more than 2.0 wt% of VO(acac)2. Several spectroscopic techniques, such as IR, ESR and NMR, have been used to study the structure and properties of V(acac)3. IR and H NMR spectrometries were used effectively for determination of VO(acac)2 in V(acac)3 however, IR showed lower LOD . FT-NIR spectroscopy was used for the determination of calcium ascorbate in blister packs, tablets, plastic bottles etc.. ... 

The XPS analysis of unwashed membranes showed that ESCA could identify the organic fouling layers of the membranes as well as the surface structure. Peak fitting regimens determined whether the materials discovered were foulants deposited (as indicated by the N (Is) data) on the surface or materials that had become chemically bound to the surface. To be chemically bound to the surface, the foulant must show an oxidation state indicative of a bond with membrane substituents. If the foulant showed a chemical composition not associated with the membrane, it was determined to be lying on the surface (physisorbed) and not chemically attached. This was the case for calcium on LFCl (Ca (2pl, 2p3)BE 350.3-346.9 eV). However, this finding does not preclude the possibility of calcium complexation with functional groups of the RO membranes used... 

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