Hang Leo awkwardly with fluorine, or iodine (7)
I believe the answer is:
halogen
'fluorine or iodine' is the definition.
(I've seen this in another clue)
'hang leo awkwardly' is the wordplay.
'awkwardly' indicates an anagram.
'hang'+'leo'='hangleo'
'hangleo' with letters rearranged gives 'HALOGEN'.
'with' is the link.
(Other definitions for halogen that I've seen before include "iodine, perhaps" , "Chlorine, fluorine, bromine, iodine or astatine?" , "I must be regarded as one" , "Element like, eg, fluorine" , "I too maybe" .)