[{"from": "human", "value": "Generate a molecule based on the given description. The molecule is the nitrogen oxoanion formed by loss of a proton from nitrous acid. It has a role as a human metabolite. It is a nitrogen oxoanion, a member of reactive nitrogen species and a monovalent inorganic anion. It is a conjugate base of a nitrous acid."}, {"from": "gpt", "value": "[N][=Branch1][C][=O][O-1]"}]