When a mixture of PhSiCl3 and (Ph)2SiCl2 is dissolved in toluene and then hydrolysed with water silicon resins are obtained.

Silicones from the hydrolysis of a mixture of (CH3)3 SiCl & (CH3)2 SiCl2

The dichloro derivative will form a long chain polymer as usual. But the growth of this polymer can be blocked at any stage by the hydrolysis product of mono-chloro derivative.

In this manner several molecules may combine to form a long chain polymer whose both the ends will be occupied by –OH groups. Such compounds are generally represented from the following formula.