cadmium(I) tetrachloroaluminate
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| Watchedfields = changed
| verifiedrevid = 428770430
| ImageFile = Cadmium(I)-tetrachloroaluminate-xtal-1987-unit-cell-CM-3D-ellipsoids.png
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| IUPACName = dicadmium(2+) bis( tetrachoridoaluminate(1−))
| OtherNames =
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 103823-00-3
| PubChem =
| SMILES = [Cd+][Cd+].Cl[Al-](Cl)(Cl)Cl.Cl[Al-](Cl)(Cl)Cl
| StdInChI=1S/2Al.2Cd.8ClH/h;;;;8*1H/q2*+3;2*+1;;;;;;;;/p-8
| StdInChIKey=MVYUNQSYEKWWLE-UHFFFAOYSA-F
}}
|Section2={{Chembox Properties
| Formula = {{chem2|Cd2[AlCl4]2}}
| MolarMass = 562.4123 g/mol
| Appearance = white crystal
| Density =
| MeltingPt = 227 ° (decomp){{cln|reason=WHAT??? The unit of measurement of melting point is not a degree, because melting point is not an angle, but a temperature! Do you mean degrees Fahrenheit or degrees Celsius??? I cannot read your mind, sorry!|date=April 2023}}
| BoilingPt =
| Solubility = }}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
| REL = Ca{{PGCH|0087}}
| PEL = [1910.1027] TWA 0.005 mg/m3 (as Cd)
| IDLH = Ca [9 mg/m3 (as Cd)]}}
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Cadmium(I) tetrachloroaluminate is the inorganic compound with the formula {{chem2|Cd2[AlCl4]2}}, a tetrachloroaluminate of cadmium(I). It was the first compound reported (1961) that contained cadmium in the +1 oxidation state and features a cadmium–cadmium bond.
Preparation and properties
{{chem2|Cd2[AlCl4]2}} was originally prepared by dissolving Cd metal in molten cadmium chloride followed by the addition of aluminium trichloride.{{Cite journal|last1=Corbett|first1=J. D.|last2=Burkhard|first2=W. J.|last3=Druding|first3=L. F.|date=January 1961|title=Stabilization of the Cadmium(I) Oxidation State. The System Cd-Cd{{su|b=2|p=1}}(AlCl{{su|b=4}}){{su|b=2}}–Cd{{su|p=2}}(AlCl{{su|b=4}}){{su|b=2}}|journal=Journal of the American Chemical Society|volume=83|issue=1|pages=76–80|doi=10.1021/ja01462a016|osti=4115153 }}
:{{chem2|CdCl2 + Cd → Cd2Cl2}}
:{{chem2|Cd2Cl2 + 2 AlCl3 → Cd2[AlCl4]2}}
Subsequent studies of the Raman vibrational spectrum indicated the presence of a cadmium–cadmium bond,{{Cite journal|last1=Corbett|first1=J. D.|date=Aug 1962|title=The Cadmium(I) Ion Cd{{su|b=2|p=2+}}. Raman Spectrum and Relationship to Hg{{su|b=2|p=2+}}|journal=Inorganic Chemistry|volume=1|issue=3|pages=700–703|doi=10.1021/ic50003a051}} which was confirmed by two separate X-ray diffraction studies of single crystals.{{Cite journal|last1=Faggiani|first1=R.|author2=Ronald J. Gillespie|author3=John E. Vekris|year=1986|title=The cadmium(I) ion, Cd{{su|b=2|p=2+}}; X-ray crystal structure of {{chem|Cd|2|(AlCl|4|)|2}}|journal=Journal of the Chemical Society, Chemical Communications|volume=1986|issue=7|pages=517–518|doi=10.1039/C39860000517}}{{Cite journal|last=Staffel|first=T.|author2=Dr. Gerd Meyer|year=1987|title=Synthesis and crystal structures of {{chem|Cd[AlCl|4|]|2|}} and {{chem|Cd|2|[AlCl|4|]|2|}}|journal=Zeitschrift für anorganische und allgemeine Chemie|volume=548|issue=5|pages=45–54|doi=10.1002/zaac.19875480505}} The compound can therefore be compared to mercury(I) (mercurous) compounds (such as mercury(I) chloride), which contain {{chem2|Hg2(2+)}}. The {{chem2|Cd\sCd}} single bonds are part of ethane-like {{chem2|Cd2Cl6}} units sharing vertices with {{chem2|AlCl4}} units, with a {{chem2|Cd\sCd}} bond length reported as 257.6 pm or 256.1pm.
{{chem2|Cd2[AlCl4]2}} is diamagnetic. It contains no unpaired electrons and reacts readily with water disproportionating to give Cd metal and {{chem2|Cd(2+)}}.File:Cadmium(I)-tetrachloroaluminate-xtal-1987-Cd-coordination-CM-3D-ellipsoids.png plot of a {{chem2|Cd2Cl6}} unit]]
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