[(CH3)3Si]14Si7O21 – ein neuer cyclischer Kieselsäuretrimethylsilylester

(CH₃)₃Si]₁₄Si₇O₂₁ — A New Cyclic Silicic Acid Trimethylsilyl Ester A new silicic acid trimethylsilyl ester was obtained by trimethylsilylation of barium chloride silicate 2 BaO · 3 BaCl₂ · 2 SiO₂. The ester was investigated by capillary gas chromatography, mass spectrometry, ²⁹Si n.m.r. spectroscopy, and thinlayer chromatography and was found to be a cycloheptasilicic acid trimethylsilyl ester (tetradecakis-trimethylsiloxicyclohepta siloxane) of the formula (CH₃)₃Si]₁₄Si₇O₂₁. The application of the new compound as a standard substance is discussed.