Hydrocarbyl is {HEAD ~ an organic group} composed solely of {TAIL ~ carbon} and, as appropriate, hydrogen, and may be aliphatic, alicyclic, aromatic, or combinations thereof, being aliphatically saturated or unsaturated, normally having not more than about one site of unsaturation 
composed solely of
Hydrocarbyl is { HEAD ~ an organic group } composed solely of { TAIL ~ carbon } and , as appropriate , hydrogen , and may be aliphatic , alicyclic , aromatic , or combinations thereof , being aliphatically saturated or unsaturated , normally having not more than about one site of unsaturation
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH