1.A study was made of the opening of the heterocycle in the series of mono- and disilacyclobutanes under the influence of alcohols and alcoholic alkali. The heterocycles with one silicon atom possess a much greater reactivity.2.Substitutents on the silicon atom, which have a positive inductive effect, increase the stability of the silicocarbon bonds of the ring, while substituents with a negative inductive effect decrease the stability.