The centrosymmetric dimer of dichloro(trimethylsiloxy)aluminium

The title molecule is dimeric, i.e. di-mu -trimethylsiloxy-bis(dichloroalum inium), [Al2Cl4(C3H9Si)(2)], and possesses exact crystallographic inversion symmetry. The O atoms of the trimethylsiloxy groups bridge the two Al atom s to form a four-membered ring. The Si-O bond distance [1.711 (3) Angstrom] , the Al-O mean bond distance [1.806 (4) Angstrom] and the mean Si-C bond d istance [1.875 (6) Angstrom] appear to agree well with standard data. Mean values for C-Si-C, O-Si-C, and Si-O-Al angles are 112.9 (3), 105.8 (2), and 131.8 (2)degrees repectively. The two ring angles O-Al-O and Al-O-Al are 8 4.43 (16) and 95.57 (16)degrees, respectively.