As {TAIL ~ alumina} has {HEAD ~ a corundum type crystal structure} , it forms sapphire or the like which is very stable as corundum 
As { TAIL ~ alumina } has { HEAD ~ a corundum type crystal structure } , it forms sapphire or the like which is very stable as corundum
OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH