Synthesis and Crystal Structure of Li2[(Me3SiCH2)3AlCH2Al(CH2SiMe3)3]—a Dilithiomethane Derivative? Reaction of (trimethylsilyl)methyllithium with the methylene-bridged aluminium tetrachloride Cl2AlCH2AlCl2 yields dilithium methylenebis[tris(trimethylsilylmethyl)aluminate] (2) as the only isolable product. All attempts for preparing the tetraalkyl analogue have been unsuccessful. The crystal structure of 2 exhibits a hexacoordinated central carbon atom with short LiC distances. Both lithium atoms and the methylene hydrogens of the AlCH2 Al unit are almost coplanar. The discussion of the structure and properties leads to the attractive description of 2 as an adduct of tris(trimethylsilylmethyl)-aluminium to dilithiomethane CH2Li2.