#nitrite  the radical -NO2 or any compound containing it (such as a salt or ester of nitrous acid)
  supertype:  #chemical_group__group__radical  (chemistry) two or more atoms bound together as a single unit and forming part of a molecule
  subtype:  #sodium_nitrite  nitrite used to preserve and color food especially in meat and fish products; implicated in the formation of suspected carcinogens

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