cyanic acid cyanate isocyanic acid PMID:19494520 HN=C=O PMID:26760716 HNCO hydrogen isocyanate isocyansaeure PMID:977566 isocyanate CAS:75-13-8 ICA carbimide Gmelin:840 chebi_ontology isozyansaeure CHEBI:29202 oxidoazanediidocarbon Reaxys:1616281 [C(NH)O] methenamide PMID:26124058 A colourless, volatile, poisonous inorganic compound with the formula HNCO; the simplest stable chemical compound that contains carbon, hydrogen, nitrogen, and oxygen, the four most commonly-found elements in organic chemistry and biology. hydracid one-carbon compound