{HEAD ~ The catalysts} comprise {TAIL ~ a metalatable particle}, such as a bound rubber, a thermoplastic polymer or a cured elastomer, that is multiply metalated with Group IA alkali metal atoms 
comprise
{ HEAD ~ The catalysts } comprise { TAIL ~ a metalatable particle } , such as a bound rubber , a thermoplastic polymer or a cured elastomer , that is multiply metalated with Group IA alkali metal atoms
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH