Mention about the right container for iron (5)
I believe the answer is:
refer
'mention' is the definition.
(thesaurus)
'about the right container for iron' is the wordplay.
'about' becomes 're' (regarding).
'the right' becomes 'r' (common abbreviation).
'container for' indicates putting letters inside.
'iron' becomes 'fe' (chemical symbol for iron).
're'+'r'='rer'
'rer' enclosing 'fe' is 'REFER'.
(Other definitions for refer that I've seen before include "Hand over for consideration (to)" , "Hand over for decision" , "Make an allusion, or send on" , "Consult" , "Draw attention" .)