Chromium alums chloride

A number of the intensely colored hydrated salts of trivalent chromium (the nitrate, sulfate, chloride, and the alum ) are doubtless familiar. The octahedral hexaaquochromium(III) ion, Cr(H20) 3, is violet, but aqueous solutions of chromic salts are often green as a result of replacement of water molecules in the complex by the anions present. The change of color occurring on heating a solution containing trivalent chromium and chloride ions should be recalled ... 

Alternate methods From violet chromium (III) chloride or dehydrated chrome alum, with ethylenedlamine hydrate or ethyl-enedlamlne, respectively. 

Molecules that coordinate strongly can often displace others from the coordination sphere. Ethylenediamine does not readily replace water from the hydrated chro-mium(III) ion, but it does readily displace pyridine. Pfeiffer has described the preparation of tris (ethylenediamine) chromium(III) chloride from trichlorotripyridine-chromium and the corresponding sulfate from dehydrated chrome alum. ... 

Hydrated chromium(III) sulphate exhibits different colours and different forms from which varying amounts of sulphate ion can be precipitated by barium chloride, due to the formation of sulphato-complexes. Chromium(III) sulphate can form alums. 

The reaction is cataly2ed by all but the weakest acids. In the dehydration of ethanol over heterogeneous catalysts, such as alumina (342—346), ether is the main product below 260°C at higher temperatures both ether and ethylene are produced. Other catalysts used include siUca—alumina (347,348), copper sulfate, tin chloride, manganous chloride, aluminum chloride, chrome alum, and chromium sulfate (349,350). 

Chemical precipitation is used in porcelain enameling to precipitate dissolved metals and phosphates. Chemical precipitation can be utilized to permit removal of metal ions such as iron, lead, tin, copper, zinc, cadmium, aluminum, mercury, manganese, cobalt, antimony, arsenic, beryllium, molybdenum, and trivalent chromium. Removal efficiency can approach 100% for the reduction of heavy metal ions. Porcelain enameling plants commonly use lime, caustic, and carbonate for chemical precipitation and pH adjustment. Coagulants used in the industry include alum, ferric chloride, ferric sulfate, and polymers.10-12... 

It is frequently said that the behavior of trivalent chromium resembles that of trivalent aluminum, presumably because of the similarity in radii of the tw o ions (A1+8, 0.45 A Cr+3, 0.55 A). The structures of the solid oxides, fluorides, and chlorides are analogous for the two metals, and both form salts of the alum type (for example, KA1(S04)2 12H20, KCr(SeC>4)2 12H20). Chromium(III) sulfide, (Cr2S3) like aluminum sulfide, cannot be made in aqueous systems. 

Oxidation states of chromium - -2, - -3, and -f-6. Oi es of chromium chronate, FeCr204, and crocoite, PbCr04. Chromium metal and its alloys ferrochrome, alloy steels, stainless steel. The aluminothermic process (Goldschrtiidt process). Electrolytic chromium. Chromium trioxide, chromic acid, dichromic acid, potassium chromate, potassium didiromate, sodium chromate, lead chromate. Equilibrium between chromate ion and dichromate ion. Chrome-tanned leather. Chromic oxide (chrome green) chromic ion, chrome alum, chromic chloride, chromic hydroxide, chromite ion. Chromous compounds. Peroxy-chromic acid. 

The sesquioxide, Cr Oa, containing trivalent chromium, is an amphoteric oxide. It yields chromic salts, such as chromic chloride, CrCla, and sulphate, Cr2(S04)a, which are very stable and show great similarity to the ferric salts and to salts of aluminium as, for example, in the formation of alums. Since, however, chromic oxide functions as a weaker base than chromous oxide, the latter having a lower oxygen content, the chromic salts are more liable to hydrolysis than the chromous salts. This is well marked in the case of the chlorides. Again, in spite of the stability of chromic salts, only a slight tendency to form simple Cr " ions is exhibited, whilst complex ions are formed much more readily, not only complex anions, as in the case of iron and aluminium, but also complex cations, as in the extensive chromammine series. In this respect chromium resembles cobalt and platinum. 

Derivation (1) Interaction of solutions of chromium chloride and sodium phosphate (2) by mixing chrome alum and disodium hydrogen phosphate. Violet, amorphous powder (not the hexahydrate) is formed that becomes crystalline on contact with water. On boiling, it is converted into green crystalline hydrate. 

Incompat Acids, alkalies, alum, ammonia water, amyl nitrite benzoates betanaphthol, phenol, calomel, chloral hydrate, copper sulfate, ferric chloride ferrous sulfate chromium trioxide (chromic acid), cinchona alkaloids, hydrocyanic acid iodides iodine Lead subacetate mercuric chloride, orthoform potassium permanganate, resorcinol, sod. bicarbonate sod. salicylate (in powder) soln arsenic and mercury iodide, spirit nitrous ether (unless prescribed with sod, bicarbonate), syrup ferrous iodide, tartar emetic tannic acid, thymol, urethane, infusions of catechu, cinchona, rose leaves and uva ursi tinctures of catechu, ferric chloride, cinchona, hamanielis iodine, kino, and rhubarb. 

But the admirable researches of Gay-Lussac and of Mitscherlich have established the fact, that in many instances, different compounds assume the same form. Thus, the following substances, and many others, take the form of the cube, tetrahedron, or regular octohedron, which are geometrically connected. Chloride of sodium (sea-salt), chloride of potassium, sal ammoniac bromide of potassium iodide of potassium sulphuret of lead fluoride of calcium bisnlphuret of iron arseniuret of cobalt sulphate of alumina and potash (alum) ammonia alum chrome alum, iron alum sesqnioxide of iron, sesquioxide of aluminum, sesquioxide of chromium. In like manner, other crystalline forms are found to be common to many different compounds, although none occurs so frequently as the cube and its congeners. 

Cadmium chloride Calcium sulfate Cetyl betaine Chromium sulfate, basic Gallic acid Lead thiocyanate Manganese chloride (ous), anhydrous Manganese chloride (ous), tetrahydrate Potassium aluminate PPG-17 Sodium alum Sodium arsenite Sodium oleoamphohydroxypropylsulfonate Sodium phosphate dibasic dihydrate Sodium polymetaphosphate... 

Compared to the relatively young history of the pure metal, aluminium compounds have been known for ages from the above-cited alum class to the more exclusive transition metal-doped aluminium oxides like ruby and sapphire (corundum varieties with chromium for the former and titanium and iron impurities for the latter) or aluminosilicate-like emeralds (a beryl type with chromium and vanadium impurities). However, to the synthetic chemist, aluminium chloride, is de facto one of the first jewels of the aluminium family. Aluminium trichloride (together with titanium tetrachloride, tin tetrachloride and boron trifluoride) is an exemplary Lewis acid that finds many applications in organic synthesis It is extensively used for instance in Friedel-Crafts alkylations and acylations, in Diels-Alder-type cycloadditions and polymerisation reactions. Its involvement in a wide range of reactions has been documented in many reviews and book chapters. ... 

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