PREVIOUSLY, u7e have described1 that hexamethyldisilane undergoes almost quantitative rearrangement to trimethyl-(dimethylsilylmethy1) silane by thermolysis at 400-450" in a sealed tube; this thermolysis differs considerably from the pyrolysis of hexamethyldisilane at low pressure. 2 Here we report the thermal reactions of polysilane carried out in a sealed tube. When pentamethyldisilane (I) was thermolysed at 300-325" for 15 hr. in a sealed ...