{HEAD ~ Suitable neutral Lewis acids} include {TAIL ~ SbF5}, Ar3 B , and BF3 
{ HEAD ~ Suitable neutral Lewis acids } include { TAIL ~ SbF5 } , Ar3 B , and BF3
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH