The zeolite {HEAD ~ Y} may have {TAIL ~ a crystal size} of less than one micron 
have
The zeolite { HEAD ~ Y } may have { TAIL ~ a crystal size } of less than one micron
OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH