The third route to the formation of the Si-O-Si-group and siloxane structures. To siloxanes through silanones

the basis of his own and literature data, the author considers and theoretically substantiates the third route to the formation and decomposition of linear and cyclic oligo- nand polysiloxanes, involving intramolecular reactions of geminal fragmentation of >Si(OR)X group with the intermediate formation (alpha-elimination) of short lived silanones R-2'Si=0. The latter further undergo polymerization or insert into the Si-X bonds (X = 0, Cl, etc.) of trapping reagents. (C) 1998 Elsevier Science S.A. All rights reserved.