Bis(trichlorosilyl)ethane was obtained both by“direct synthesis"and by silicon hy-dride addition．This was ethanolyzed and methylated to mono-to tetra·methyl penta-to diethoxy disilyl ethanes．These monomers were hydrolyzed in presence of ether and diluted hydrochloric acid．Only the pentafunctional monomer gave entirely insoluble and infusible polymer；all the other monomers gave partly polymers and partly distillable oligomers．The tetrafunc-tional monomer yielded a cyclic dimer closely similar to octamethylcyclotetrasiloxane，the trifunctional monomer，a fused ring tetramer。while the difunctional monomer a cyclic dimer．The structure and the mechanism of formation of these oligomers were discussed．