The symbol {HEAD ~ FC hereinafter} stands for {TAIL ~ fluorocarbon} and numbers are chosen for convenience in referring to these fluorocarbon compounds 
stands for
The symbol { HEAD ~ FC hereinafter } stands for { TAIL ~ fluorocarbon } and numbers are chosen for convenience in referring to these fluorocarbon compounds
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH