Awful, fouler in a corrosive gas (8)

I believe the answer is:

fluorine

I'm a little stuck... Click here to teach me more about this clue!

'a corrosive gas' is the definition.
'fluorine' can be an answer for 'gas' (I've seen this before). I'm not certain of the 'a corrosive' bit.

'awful fouler in' is the wordplay.
'awful' indicates an anagram.
'fouler'+'in'='foulerin'
'foulerin' anagrammed gives 'FLUORINE'.

Can you help me to learn more?

(Other definitions for fluorine that I've seen before include "Poisonous pale yellow gas" , "highly toxic stuff" , "Element, symbol F" , "A poisonous halogen gas" , "Gaseous element" .)

I've seen this clue in the Sydney Morning Herald.

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