Abstract New SiMe 2 R-substituted derivatives of decamethylcyclopentasilane were prepared by different pathways. The halogen compounds where R F, Cl, Br or I exhibit a strong influence of the substituent on the physical properties of the silicon ring. Hydrolysis of the halides gives a hydroxy compound (R OH) and takes place extremely slowly, whereas the formation of polysiloxanes is favoured.
