Chromium III chloride

Sulphur dichloride oxide (thionyl chloride) on the hydrated chloride can also be used to produce the anhydrous chloride in certain cases, for example copper(II) chloride and chromium(III) chloride ... 

This is the most common and stable state of chromium in aqueous solution. The Cr ion, with 2d electrons, forms mainly octahedral complexes [CrX ], which are usually coloured, and are kweticallv inert, i.e. the rate of substitution of X by another hgand is very slow consequently a large number of such complexes have been isolated (see below, under chromium(III) chloride). 

At one time these were the only commercially important non-silane coupling agents. Supplied by du Pont under the Volan tradename, they are coordination complexes of carboxylic acids with chromium(III) chlorides. Hydrolysis of the... 

Chrom-bleii n. lead chromate, -bleispat, m. (Min.) crocoite. -braun, n. chrome brown, -chlorid, n. chromic chloride. chromium(III) chloride, -chlorilr, n, chromous chloride, chromium(II) chloride, -druck, m. (Calico) chrome printing. 

The condensation is usually carried out by adding a solution containing equimolar amounts of the allyl halide and the aldehyde or ketone to a solution of at least two equivalents of chromium-(II) chloride in THF at 0 5°C. Frequently, the less precious component is used in 50-100% excess. Although commercially available anhydrous chromium(II) chloride can be utilized (Method B), its in situ preparation from chromium(III) chloride and lithium aluminum hydride (Method A) is often preferred. The removal of chromium and aluminum hydroxide, which are formed on aqueous workup, can be accomplished by filtration in the presence of a filtration aid. 

Method A To a stirred suspension of 4.28 g (27 mmol) of anhyd chromium(III) chloride in 100 ml. of anhyd THF in a 500-mL three-necked, round-bottom flask, under nitrogen, is added 0.51 g (13.4 mmol) of LiAlH4 at 0 °C in small portions with vigorous stirring. After the evolution of hydrogen has ceased, stirring is continued at 20 C for 30 min. 

Step 3 Name the anion and combine the names of chromium(III) chloride... 

Step 4 If H20 is present, add hydrate with a chromium(III) chloride hexahydrate... 

A series of chromium(III) amidinates containing additional pyrazolato, triazolato, or tetrazolato ligands have recently been reported. Treatment of anhydrous chromium(III) chloride with 2 or 3 equivalents of LilMeCfNBu l or Li[MeC(NPr )2] in THF at room temperature afforded [MeC(NBu02]2CrCl(THF) and [MeC(NPr )2]3Cr in 78 and 65% yields, respectively (Scheme 120). ... 

The synthesis of [Cr(NH3)6]Cl3 from anhydrous chromium(III) chloride and liquid ammonia in the presence of catalytic quan-... 

Chromium (II) chloride solutions can be prepared by any one of several different procedures. If pure electrolytic chromium is available, the procedure of Holah-Fackler (see synthesis 4) is recommended. Some modification as noted at the end of this procedure may be desirable. If metallic chromium is not available, commercial chromium(III) chloride may be reduced electrolytically (a suitable divided cell is needed), or the reduction may be effected by zinc and hydrochloric acid. The latter procedure, which starts with the most commonly available reagents and apparatus, is described here. 

The crude product may be recrystallized by the same procedure as that used for [Cr(NH3)6]Cl3 except that the cold acid solution is treated with about 4 volumes of cold alcohol to precipitate the product. The crystals are washed with alcohol and ether and allowed to dry. The crude yield is 15.3 g. of [Cr(en)3]Cl3-3H20 or about 70% based on the original chromium(III) chloride used. The final recrystallized yield is 11.5 g. or 52%. Rapid work-up of the solution gives rise to less olationf and higher yields. 

Chromium(II) chloride, 6 528t, 531, 564t Chromium(III) chloride, 6 532 physical properties, 6 528t Chromium(IV) chloride, 6 535 Chromium(III) chloride hexahydrate, physical properties, 6 528t Chromium chromate coatings, 76 219—220 Chromium complexes, 9 399 Chromium compounds, 6 526-571 analytical methods, 6 547-548 economic aspects, 6 543-546 environmental concerns, 6 550—551 health and safety factors, 6 548-550 hydrolysis, equilibrium, and complex formation constants, 6 530t manufacture, 6 538-543... 

This is prepared by passing dry hydrogen chloride over chromium, or hydrogen over anhydrous chromium(III) chloride. It is a white solid. If pure chromium is dissolved in dilute hydrochloric acid in the absence of air, a blue solution of the hydrated chloride, containing the hexaaquo-ion [Cr(H20)6]2+. is obtained. The same solution is also obtained by reduction of the + 6 oxidation state (through the + 3) using a solution of a dichromate(VI) and reducing with zinc and hydrochloric acid ... 

Chlorogermane, 3992 Chromium(II) chloride, 4052 Chromium(III) chloride, 4127 Chromium pentafluoride, 4226... 

Also, the compound may be prepared by the reduction of chromium(III) chloride with hydrogen at 500 to 600° C ... 

Chromium(III) chloride hexahydrate may be prepared by treating chromium hydroxide with hydrochloric acid ... 

The anhydrous chromium (III) chloride may be obtained by heating the hydrated salt CrCls 6H2O with SOCI2 and subliming the product in a stream of chlorine at 600°C. Alternatively, the red-violet anhydrous chloride can be obtained by passing chlorine gas over a mixture of chromic oxide and carbon ... 

Chromium(III) chloride at elevated termperatures decomposes to chromi-um(II) chloride and chlorine ... 

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