Quinine is an alkaloid, a naturally occurring chemical compound. Zinc sulfate is an inorganic compound and dietary supplement. It is an organic salt classified as a quaternary ammonium compound. Pyruvate is an important chemical compound in biochemistry. Naphthalene is an organic compound with formula . Carbazole is an aromatic heterocyclic organic compound. Benzimidazole is a heterocyclic aromatic organic compound. Isoquinoline is a heterocyclic aromatic organic compound. Indole is an aromatic heterocyclic organic compound with formula CHN. Litharge is the most commonly used inorganic compound of lead. Reaction of the anhydrous compound with sodium cyclopentadienide gives cobaltocene . Azobenzene is the prototypical aromatic azo compound. Chlorine dioxide is a neutral chlorine compound. Ferrocene was not the first organometallic compound known. Fluorescein is an organic compound and dye.