While {HEAD ~ metallic sodium} is usually employed as {TAIL ~ sodium}, sodium alloys containing a small amount of other alkali metals or alkaline earth metals may be used so long as their melting points are lower than about 105° C 
is usually employed as
While { HEAD ~ metallic sodium } is usually employed as { TAIL ~ sodium } , sodium alloys containing a small amount of other alkali metals or alkaline earth metals may be used so long as their melting points are lower than about 105 ° C
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH