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)]]