Termination by unstable counter-ion

In anionic polymerization, the counter-ions are usually simple, derived mainly from a single element, as a whole they are therefore highly stable. On of the most important termination mechanisms is absent, and the polymeriza- 

Even at low temperatures, the ions BF and BF3OH - are decomposed to BF3 and a combining anion [95] 

Several compound counter-ions are known which are stable even at temperatures around 273 K. They are SbF6, AsF6, PF, CF3SO, FSO, and C104 . Initiators producing these counter-ions can start living (when transfer is prevented) or at least stationary polymerizations. 

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