{HEAD ~ The content} of Mn, if any, is preferably {TAIL ~ from 1 to 9 mol %} 
{ HEAD ~ The content } of Mn , if any , is preferably { TAIL ~ from 1 to 9 mol % }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL