#fixing_agent  a compound that sets or fixes something
  supertype:  chemical_compound__compound  (chemistry) a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight
  subtype:  fixative.fixing_agent  a compound (such as ethanol or formaldehyde) that fixes tissues and cells for microscopic study
  subtype:  hypo__sodium_thiosulphate__sodium_thiosulfate  a compound used as a fixing agent in photographic developing

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