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