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