While the relative chemical simplicity of these prototypical intermetallic clathrates is ideal for understanding clathrate structure property relationships, {HEAD ~ synthesis} in the binary Na—Si system has historically been complicated by {TAIL ~ the simultaneous formation} of the two different structure types , which are characterized by nearly identical compositions 
While the relative chemical simplicity of these prototypical intermetallic clathrates is ideal for understanding clathrate structure property relationships , { HEAD ~ synthesis } in the binary Na — Si system has historically been complicated by { TAIL ~ the simultaneous formation } of the two different structure types , which are characterized by nearly identical compositions
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH