Stink about a hydrogen-nickel compound? Unsuccessful name for element (7)
I believe the answer is:
hahnium
'for element' is the definition.
(hahnium is a kind of element)
'stink about a hydrogen-nickel' is the wordplay.
'stink' becomes 'hum' (I've seen this in other cluesasomething with a bad).
'about' means one lot of letters goes inside another.
'hydrogen' becomes 'H' (H is the chemical symbol for hydrogen).
'nickel' becomes 'Ni' (Ni is the chemical symbol for nickel).
'a'+'h'+'ni'='ahni'
'hum' enclosing 'ahni' is 'HAHNIUM'.
'compound? unsuccessful name' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Another definition for hahnium that I've seen is " as elements were called earlier".)