CrCl2 Chromium chloride

CAS 10049-05-5 EINECS/ELINCS 233-163-3 Synonyms Chromium chloride Chromium (II) chloride Chromium (II) chloride (1 2) Chromium (II) chloride anhydrous Chromium dichloride Chromous chloride Empihcai Cl2Cr Formuia CrCl2... 

Chromium(IJ) chloride, chromous chloride, CrCl2- White solid (Cr plus HCl gas) dissolving to give a blue solution. Forms hydrates, widely used as a reducing agent. 

The anhydrous hahdes, chromium (II) fluoride [10049-10-2], chromium (II) bromide [10049-25-9], CrBr2, chromium (II) chloride [10049-05-5], CrCl2, and chromium (II) iodide [13478-28-9], 03x1, are prepared by reaction of the hydrohaUde and pure Cr metal at high temperatures, or anhydrous chromium (II) acetate [15020-15-2], Cr2(CH2COO)4, atlower temperatures, or by hydrogen reduction of the Cr(III) hahde at about 500—800°C (2,12). 

A pale blue-green complex [CrCl2(PMT)2] (jU2ffK = 4.55BM) of pentamethylenetetrazole (PMT) has been obtained by the addition of solid PMT in excess to a solution of hydrated chromium(II) chloride in a 50% DMP/MeOH mixture.11)2 Pyrazines and Cr2+ give intensely coloured pyrazine green products (Section 35.4.2.5.iv). 

Other reagents that have been used to reduce support-bound aromatic nitro compounds include phenylhydrazine at high temperatures (Entry 5, Table 10.12), sodium borohydride in the presence of copper(II) acetylacetonate [100], chromium(II) chloride [196], Mn(0)/TMSCl/CrCl2 [197], lithium aluminum hydride (Entry 3, Table... 

Diastereoselective macrocyclizjation.1 A key step in a synthesis of the 14-membered cembranoid asperdiol (4) involves intramolecular cyclization of the aldehydo allylic bromide (1) with chromium(II) chloride. The intermolecular version of this reaction is known to be awft-selective (8,112). Treatment of racemic 1 with CrCl2 (5 equiv., THF) results in a 4 1 mixture of the two anri-diastereomers 2 and 3 in 64% combined yield. The stereochemistry of this cyclization is evidently controlled by the remote epoxide group. The natural product was obtained by deprotection of 2 (Na/NH3, 51% yield). 

Metal chloride complexes (59) with structures analogous to that of the samarium complex (50) have been obtained by the reaction of (57) with titanium or zirconium tetrachlorides via elimination of LiCl. Equimolar reaction of (57) and CrCl2(thf)2 has been shown to yield binuclear chromium complex (60), whilst reaction with a twofold excess of CrCl2(thf)2 affords a partially substituted tetranuclear complex (61). ... 

Differ by the exchange of a H2O molecule and another ligand in the coordination sphere Example The solid hexahydrate of chromium(Ill) chloride, CrCb -6H20, is known in three forms [Cr(H20)6]Cl3, [CrCl(H20)5]Cl2 H2O, and [CrCl2(H20)4]Cl HjO. 

Aqueous solutions of some compounds that contain chromium. (Left to right) Chromium(II) chloride (CrCl2) is blue chromium(III) chloride (CrClj) is green potassium chromate (K2Cr04) is yellow potassium dichromate (K2Ct207) is orange. 

CrO black Cr(OH)2 chromium(II) hydroxide basic CrCl2 anhydr. colorless aq. It. blue chromium (II) chloride... 

This method by Sullivan etal. (2000) is based on the conversion of reduced inorganic sulfur to H2S by hot acidic chromium(II) chloride (CrCl2) solution. The hydrogen sulfide (H2S) evolved is trapped in a zinc acetate solution as ZnS, and subsequently quantified by iodometric titration (see Fig. 5.1). The reduced inorganic sulfur compounds measured are (i) pyrite and other iron disulfides (ii) elemental sulfur and (iii) acid volatile sulfides (e.g. greigite and mackinawite). The method can be made specific to the iron disulfide fractions if pre-treatments are used to remove the acid volatile sulfides and elemental S fractions. 

The crystal structure of CrCl2-4H20 shows the chromium(II) ion to be surrounded by a grossly distorted octahedron of four water and two chloride ligands. The single-crystaP and reflectance spectra of this complex have been measured, and the complex band system centered on 14,000 cm. has been interpreted on the basis of these distortions. Aqueous solution spectra between 8,000 and 20,000 cm. are identical for all... 

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