containing compound the molar ratio of the lithium terminated rubbery polymer to halogen atoms in the halogenated silicon containing compound or halogenated tin containing compound is preferably be within the range of 3 n to n 1 n wherein n represents the number of halogen atoms that are bonded directly to silicon atoms or tin atoms in the halogenated silicon containing compound or the halogenated tin containing compound for instance in the case of silicon tetrachloride the molar ratio of living metal end groups in the polymer to the silicon tetrachloride would be within the range of 1 2 to 3 4 and would preferably be 3 4 the temperature at which this step of the process is carried out is not particularly critical however it will generally be carried out at a temperature of 0 u00b0 c to about 150 u00b0 c most commonly this step of the process will be done at ambient temperature during this step of the process the halogenated silicon containing compound or halogenated tin containing compound reacts with the metal terminated polymer so as to produce a polymer which is terminated with halogenated silicon moieties or halogenated tin moieties wherein the halogenated silicon or tin moieties contain at least one halogen atom which is bonded directly to a silicon atoms or a tin.