5-COORDINATE SI COMPOUNDS AS INTERMEDIATES IN THE SYNTHESIS OF SILICATES IN NONAQUEOUS MEDIA

Sodium silicoglycolate, an organosilicon compound in which silicon is in 5-coordination with respect to oxygen, is shown to be a reaction in termediate in the synthesis of a purely siliceous sodalite with ethyle ne glycol as solvent. The presence of silicon-29 nuclear magnetic reso nances at -105.5 +/- 0.3 parts per million in solution and -102.7 part s per million in the solid state as well as x-ray powder diffraction p atterns demonstrate that 5-coordinate silicon is intimately involved i n the synthesis. Silicon compounds of the 5-coordinate type are highly reactive and are promising starting materials for the synthesis of no vel silicone polymers, molecular sieves, glasses, semiconductors, and ceramics. We have used sodium silicoglycolate to prepare the molecular sieve silicalite as well as sodalites of different compositions.