{HEAD ~ The reactants} can be heated between about 650° C. and {TAIL ~ 670° C.} to produce type II clathrates Na24Si136 and K24Si136 
heated between
{ HEAD ~ The reactants } can be heated between about 650 ° C. and { TAIL ~ 670 ° C. } to produce type II clathrates Na24Si136 and K24Si136
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH