Cadmium(I) tetrachloroaluminate is the inorganic compound with the formula 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
Cd2[AlCl4]2 was originally prepared by dissolving Cd metal in molten CdCl2 followed by the addition of AlCl3.[2]
CdCl2 + Cd → Cd2Cl2
Cd2Cl2 + 2 AlCl3 → Cd2[AlCl4]2
Subsequent studies of the Raman vibrational spectrum indicated the presence of a cadmium–cadmium bond,[3] which was confirmed by two separate X-ray diffraction studies of single crystals.[4][5] The compound can therefore be compared to mercury(I) (mercurous) compounds (such as mercury(I) chloride), which contain Hg2+2. The Cd−Cdsingle bonds are part of ethane-like Cd2Cl6 units sharing vertices with AlCl4 units, with a Cd−Cd bond length reported as 257.6 pm[4] or 256.1pm.[5]
Cd2[AlCl4]2 is diamagnetic. It contains no unpaired electrons and reacts readily with water disproportionating to give Cd metal and Cd2+.
^Corbett, J. D.; Burkhard, W. J.; Druding, L. F. (January 1961). "Stabilization of the Cadmium(I) Oxidation State. The System Cd-Cd1 2(AlCl 4) 2–Cd2 (AlCl 4) 2". Journal of the American Chemical Society. 83 (1): 76–80. doi:10.1021/ja01462a016. OSTI4115153.
^Corbett, J. D. (Aug 1962). "The Cadmium(I) Ion Cd2+ 2. Raman Spectrum and Relationship to Hg2+ 2". Inorganic Chemistry. 1 (3): 700–703. doi:10.1021/ic50003a051.
^ abFaggiani, R.; Ronald J. Gillespie; John E. Vekris (1986). "The cadmium(I) ion, Cd2+ 2; X-ray crystal structure of Cd 2(AlCl 4) 2". Journal of the Chemical Society, Chemical Communications. 1986 (7): 517–518. doi:10.1039/C39860000517.
^ abStaffel, T.; Dr. Gerd Meyer (1987). "Synthesis and crystal structures of Cd[AlCl 4] 2 and Cd 2[AlCl 4] 2". Zeitschrift für anorganische und allgemeine Chemie. 548 (5): 45–54. doi:10.1002/zaac.19875480505.
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