The methylchlorodisilanes SiCl2Me SiCl2Me (1), SiCl2Me SiClMe2 (2) and SiClMe2 SiClMe2 (3) disproportionate in the presence of a basic catalyst into methylchloromonosilanes and various methylchlorooligosilanes. Oligosilanes involving up to seven silicon atoms were identified by means of 29Si-, 13C-1H-NMR and GC-MS measurements. Formation of methylchlorooligosilanes is thoughtto take place via silylene ...