Pet shop has mixed chemicals (10)

I believe the answer is:

phosphates

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'chemicals' is the definition.
The answer and definition can be both substances as well as being plural nouns.
Maybe there's an association between them I don't understand?

'pet shop has mixed' is the wordplay.
'mixed' indicates an anagram.
'pet'+'shop'+'has'='petshophas'
'petshophas' is an anagram of 'PHOSPHATES'.

Can you help me to learn more?

I've seen this clue in The Hindu.

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