Abstract: | New Hypersilanides of the Earth Metals Aluminium, Gallium, and Indium The dialkylaluminiumchlorides R2AlCl (with R = Me, Et; Me = CH3, Et = C2H5) react with base‐free lithium‐tris(trimethylsilyl)silanide (Li–Hsi; Hsi = –Si(SiMe3)3), forming the pyrophoric dialkyl aluminiumhypersilanides R2Al–Hsi. The methyl compound is dimeric in solid state (triclinic space group P1, Z = 1 dimer), as in Al2Me6 the association takes place by two Al–Me–Al bridges, forming a centrosymmetric molecule of approximately C2h point‐symmetry. Contrary to this (Me2GaCl)2 and Li–Hsi form a mixture of (MeGa(Hsi)Cl)2 and Me3Ga–Hsi]Li. The monochloride again is a centrosymmetric, chlorine‐bridged dimer (monoclinic space group P21/n, Z = 2 dimers). The extremely air sensitive gallate can be prepared from GaMe3 and Li–Hsi (1 : 1 ratio), as well as the homologous Me3Ga–Hsi]Na and Me3Ga–Hsi]K from GaMe3 and the corresponding alkalimetal hypersilanides. The 1 : 1 toluene‐solvat of the sodium salt crystallizes in the orthorhombic space group Pbca (Z = 8) with polymeric zig‐zag‐chains, in which the toluene‐capped Na‐ions act as GaMe…Na…Me2Ga‐bridges between Me3Ga–Hsi]– anions. The reaction of InCl3 with Li–Hsi (1 : 3 ratio) mainly gives LiCl, metallic In and the “dihypersilyl” Hsi–Hsi. Ruby‐red (Hsi)2In–In(Hsi)2 could also be obtained in low yield and characterized by X‐ray structure elucidation (space group P21/c, Z = 4). The 1H, 13C, 29Si and 7Li NMR‐ and the vibrational spectra of the hypersilanides have been measured and discussed. |