Nonhygroscopic, anionic pentacoordinate silicate

摘要

Nonhygroscopic, anionic pentacoordinate silicate, for example, ##STR1## soluble in commonly used organic solvents, and useful as a source of fluoride, cyanide or azide anion and as a catalyst or cocatalyst in polymerization systems, for example, the polymerization of methyl methacrylate.