Die Konstitution des Tetramethylammoniumsilicats der Zusammensetzung 1,0 N(CH3)4OH 1,0 SiO2 · 8,0–8,3 H2O

By means of paperchromatographic, kinetic and X-ray methods it is shown that the tetramethylammonium silicate of the composition 1 N(CH₃)₄OH · 1 SiO₂ · ～8 H₂O has not – as hitherto supposed – the constitution of a poly- or phyllosilicate, but that of a tetra-anhydrido-bis-cyclotetrasilicate (double-fourringsilicate), (CH₃)₄N]₈Si₈O₂₀] · ～69 H₂O. Its trimethylsilylation by means of hexamethyldisiloxane gives the corresponding, crystalline trimethylsilyl ester (CH₃)₃Si]₈Si₈O₂₀], which has been characterised by mass spectroscopy.