Chromium chloride, structure

Chromium, tetraaquadichloro-chloride dihydrate hydrate isomerism, 1, 183 Chromium, tetrabromo-solvated, 3, 758 synthesis, 3, 763 Chromium, tetrachloro-antiferromagnetic, 3, 761 ferromagnetic magnetic properties, 3,7559 optical properties, 3,759 structure, 3,759 solvated, 3. 758 synthesis. 3, 759 Chromium, tetrachlorooxy-tetraphenylarsenate stereochemistry, 1,44 Chromium, tetrahalo-, 3,889 Chromium, tetrakis(dioxygen)-stereochemistry, 1,94 Chromium, triamminediperoxy-structure. 1, 78 Chromium, tricyanodiperoxy-structure, 1, 78 Chromium, trifluoro-electronic spectra, 3, 757 magnetic properties, 3, 757 structures, 3, 757 synthesis, 3, 756 Chromium, trihalo-clcctronic spectra, 3, 764 magnetic properties, 3, 764 structure, 3, 764 synthesis, 3, 764 Chromium, tris(acetylacetone)-structure. 1, 65 Chromium, tris(bipyridyl)-... 

Plaper et al. (2002) use a stand-alone Discussion section, rather than a combined R D section. According to the move structure in figure 5.1, a separate Discussion section should begin with a brief reminder of a specific result or set of results this is essentially how Plaper et al. (2002) begin. The authors first remind the readers about the study in general (in the first two sentences) then, in the third sentence, they remind the readers specifically about the Pro-Tox (C) assay with chromium chloride. 

Tlie body-centered cubic structure of chromium is the same as the cesium chloride structure illustrated in Fig. 2-l,a, with both Cs and Cl ions replaced by Cr atoms it is redrawn in b ig. 20-2, with the z-axis being considered vertictil. f- or each of the six orbitals (a = 1, 2,. .., 6) on each atom, we construct a Bloch sum over the N, atoms in the system, in analogy with Eq. (3-19) ... 

Chromium, tetraaquadichloro-chloride dihydrate hydrate isomerism, 183 Chromium, tetrachlorooxy-tetraphenylarsenate stereochemistry, 44 Chromium, triamminediperoxy-structure, 78... 

The cyclometalation of o-lithium dimethylaminobenzene with chromium chloride proceeds to give the five-membered ring as shown in eq. (13.24) [26,36]. Many organometallic intramolecular-coordination compounds containing the five-membered ring structure of organochromium compounds have been synthesized and the structure was determined by X-ray diffraction studies as shown in the book Organometallic Intramolecular-coordination Compounds [26]. 

Garwood et al. [36,38] reported that subsequent to dealumination with EDTA a significant amount of silicon could be digested and removed by refluxing with 1 N NaCl (or other salt) solutions while silicon was less readily removable after dealumination with chromium chloride. This behavior was considered to evidence the incorporation of chromium into framework vacancies left after release of aluminum, resulting in healing of the lattice ruptures and, hence, in more stable structures. 

Modification of the metal itself, by alloying for corrosion resistance, or substitution of a more corrosion-resistant metal, is often worth the increased capital cost. Titanium has excellent corrosion resistance, even when not alloyed, because of its tough natural oxide film, but it is presently rather expensive for routine use (e.g., in chemical process equipment), unless the increased capital cost is a secondary consideration. Iron is almost twice as dense as titanium, which may influence the choice of metal on structural grounds, but it can be alloyed with 11% or more chromium for corrosion resistance (stainless steels, Section 16.8) or, for resistance to acid attack, with an element such as silicon or molybdenum that will give a film of an acidic oxide (SiC>2 and M0O3, the anhydrides of silicic and molybdic acids) on the metal surface. Silicon, however, tends to make steel brittle. Nevertheless, the proprietary alloys Duriron (14.5% Si, 0.95% C) and Durichlor (14.5% Si, 3% Mo) are very serviceable for chemical engineering operations involving acids. Molybdenum also confers special acid and chloride resistant properties on type 316 stainless steel. Metals that rely on oxide films for corrosion resistance should, of course, be used only in Eh conditions under which passivity can be maintained. 

Recently it was found that ot-trichloromethyl carbinols and their ethers, a class of compounds which is easily obtainable in large structural variety, can be reduced by chromium(II) chloride in water or aqueous DMF to synthetically very interesting products (Table 5, No. 6-8) . Thus, trichloromethyl-substituted secondary alcohols and ethers give (Z)-configurated vinyl chlorides in one step (Eqs. (70)-(72)). 

The tris and bis complexes of acetylacetone (2,4-pentanedione) (167) with chromium(III) have been known for many years (168,169).739 The tris compound is generally prepared by the reaction of an aqueous suspension of anhydrous chromium(III) chloride with acetylacetone, in the presence of urea.740 Recently a novel, efficient synthesis of tris(acetylacetonato)chromium-(III) from Cr03 in acetylacetone has been reported.741 The crystal structure of the tris complex has been determined.744 A large anisotropic motion was observed for one of the chelate rings, attributed to thermal motion, rather than a slight disorder in the molecular packing. 

Chromium is unusual in that it forms a stable hexakis O-bonded urea complex. The complex was first prepared as the chloride salt by Pfeiffer804 and a crystal structure of the complex salt [Cr OC(NH2)2 6][Cr(CN)6]-2DMSO>2EtOH has recently been reported.805 Coordination at chromium(IH) is octahedral r(Cr—O) is in the range 1.96-1.98 A. The reduction of the perchlorate salt of this complex to a chromium(II) species has been studied polarographically.806 Detailed studies of the luminescence spectra of several salts of the chromium urea complex have been reported.807,808... 

These have been known for many years.1052-1054 Chromium(III) is approximately octahedral ( ie(f = 3.69-4.1 BM) the compounds have a layer structure. In the chloride, r(Cr—Cl) is 5.76 A between layers and 3.46 A within layers. The iodide is isomorphous with the chloride and the bromide has a similar but distinct structure. All may be prepared by the direct halogenation of the metal. Other methods are available, e.g. CrCl3 may be prepared by heating Cr203-xH20 in CCU vapour at 650 °C.1055 The anhydrous halides are insoluble in water, however reducing agents such as zinc catalyze dissolution. The trichloride reacts with liquid ammonia to form ammine complexes. 

Therefore, in such heterogeneous polymerizations, almost all industrial catalysts are supported, for example on silica, whereas the typical Ziegler s titanium catalysts are by definition supported on magnesium chloride. These catalysts are adsorbed at the surface or incorporated into the crystal structure of the support. Other catalysts, such as Phillips chromium catalysts, can be coupled at the support surface by a chemical bond. 

Carbon tetrafluoride, 1 34 3 178 Carbon tetraiodide, 3 37 Carbonyl azide, formation of, by carbohydrazide, 4 35 Carbonyl fluoride, 6 155 Carbonyls, metal, 2 229 metal, nomenclature of, 2 264 structure of, 2 232 Catalysts, beryllium chloride, 5 25 boron fluoride, 1 23 chromium(III) oxide gel, 2 190... 

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