The most common and most likely answer to this crossword clue is the 8 letter word SULPHATE
I've seen this crossword clue in The Times
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More clues leading to the result SULPHATE
Buddy explains!
The straight part
We know that "Chemical" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case chemical = sulphate.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SULPHATE mean?
SULPHATE noun- Any ester of sulfuric acid.
- Any salt of sulfuric acid.
- To treat something with sulfuric acid, a sulfate, or with sulfur dioxide.
- (of a lead-acid battery) To accumulate a deposit of lead sulfate.