In this embodiment, {HEAD ~ the reactants} are heated between {TAIL ~ about 580° C.} and 590° C. to produce type I clathrates Na8Si46 and K8Si46 
In this embodiment , { HEAD ~ the reactants } are heated between { TAIL ~ about 580 ° C. } and 590 ° C. to produce type I clathrates Na8Si46 and K8Si46
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH