The process 7, wherein {HEAD ~ the first metal oxide} and {TAIL ~ the second metal oxide} comprise the same metal oxide 
The process 7 , wherein { HEAD ~ the first metal oxide } and { TAIL ~ the second metal oxide } comprise the same metal oxide
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH