First coal solvation involves {HEAD ~ formation} of {TAIL ~ free radicals} which are stabilized by hydrogen 
First coal solvation involves { HEAD ~ formation } of { TAIL ~ free radicals } which are stabilized by hydrogen
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH