{HEAD ~ J} is one or more of Y, La, Ce, Eu, Th, {TAIL ~ U}, and the remaining lanthanides and j is from 0 to 3 
is
{ HEAD ~ J } is one or more of Y , La , Ce , Eu , Th , { TAIL ~ U } , and the remaining lanthanides and j is from 0 to 3
HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH