C. Chuit et al., INTRAMOLECULAR BASE STABILIZATION OF SILICENIUM IONS - A NEW ROUTE TOSILICONIUM IONS, Angewandte Chemie, International Edition in English, 32(9), 1993, pp. 1311-1313
The silicon atom is pentacoordinate in cations of salts like 1, which
can be prepared, for instance, in a redox reaction of the correspondin
g silane (with I2, X = I) or transformation with electrophiles like Ph
COCl (X = Cl) or Ph3C+BF4- (X = BF4). These compounds were completely
characterized; conductivity titrations confirm that they are ionic.