Chromium(II) chloride 4168493 212594131 2008-05-15T13:07:46Z Rifleman 82 1255637 +msds {{Chembox new | Name = Chromium(II) chloride | IUPACName = Chromium(II) chloride | OtherNames = Chromous chloride | Section1 = {{Chembox Identifiers | CASNo = 10049-05-5}} | Section2 = {{Chembox Properties | Formula = CrCl<sub>2</sub> | MolarMass = 122.92 g/mol | MeltingPt = 824°C | BoilingPt = 1120°C}} | Section7 = {{Chembox Hazards | ExternalMSDS = [http://msds.chem.ox.ac.uk/CH/chromium_II_chloride.html Oxford MSDS] | EUClass = Harmful}} | Section8 = {{Chembox Other | OtherCations = [[Chromium(III) chloride]]}} }} '''Chromium(II) chloride''' is the [[chemical compound]] with the [[chemical formula|formula]] [[Chromium|Cr]][[Chloride|Cl]]<sub>2</sub>. This white, crystalline solid is used for the synthesis of other chromium complexes. CrCl<sub>2</sub> is hygroscopic. It dissolves in water to give bright blue solutions that are easily oxidized by air to give Cr(III)-containing products. CrCl<sub>2</sub> crystallizes in the [[cadmium chloride]] motif. ==Synthesis== CrCl<sub>2</sub> is produced by reducing [[chromium(III) chloride]] with [[hydrogen]] at 500 °C:<ref>{{cite journal | author = Burg, A. B. | title = Anhydrous Chromium(II) Chloride | journal = [[Inorg. Synth.]] | volume = 3 | pages = 150-153 | doi = 10.1002/9780470132340}}</ref> :CrCl<sub>3</sub> + 1/2H<sub>2</sub> → CrCl<sub>2</sub> + HCl Small scale preparations can use LiAlH<sub>4</sub>, or related reagents, to reduce CrCl<sub>3</sub> :4 CrCl<sub>3</sub> + LiAlH<sub>4</sub> → 4 CrCl<sub>2</sub> + LiCl + AlCl<sub>3</sub> + 2 H<sub>2</sub> Commonly, it is generated in situ by reduction of CrCl<sub>3</sub> with zinc. ==Uses== Chromium(II) chloride is used as precursor to other inorganic and organometallic chromium complexes. Alkyl halides and nitroaromatics are reduced by CrCl<sub>2</sub>. The moderate electronegativity of chromium and the range of substrates that CrCl<sub>2</sub> can accommodate make [[organochromium compound|organochromium reagents]] very synthetically versatile.<ref>Kazuhiko Takai, K.; Loh, T.-P. "Chromium(II) Chloride" in Encyclopedia of Reagents for Organic Synthesis John Wiley & Sons: New York; 2005. DOI: 10.1002/047084289X.rc166.</ref> it is a reagent in the [[Nozaki-Hiyama-Kishi reaction]]. ==References== * {{Greenwood&Earnshaw}} <references/> ==External links== * http://www.osha.gov/SLTC/healthguidelines/chromium2/recognition.html [[Category:Chromium compounds]] [[Category:Chlorides]] {{inorganic-compound-stub}} [[ar:كلوريد كروم ثنائي]] [[pl:Chlorek chromu(II)]] [[ru:Хлорид хрома(II)]]