C9H9NO3

C9H9NO3 is the molecular formula for a class of organic compounds that contains nine carbon atoms, nine hydrogen atoms, one nitrogen atom, and three oxygen atoms. It does not designate a single compound, but rather any of several constitutional isomers that share this formula.

The formula has a molecular weight of about 179.17 g/mol and a degree of unsaturation (DBE) of 6, which is consistent with an aromatic ring and additional multiple bonds or rings. With only nine carbons, a benzene ring is a common structural motif in many isomers of C9H9NO3.

Possible structural features include a nitro group, amino group, or other nitrogen-containing substituent, combined with oxygen-containing groups such as carbonyls (esters or amides) or hydroxyls. The three oxygens can accommodate one nitro group (NO2) plus a carbonyl or an additional hydroxy or ester unit. Because many isomers share this formula, the exact arrangement of atoms can vary widely.

Properties such as melting point, solubility, and reactivity depend on the specific isomer. Identification and confirmation require spectroscopic methods (nuclear magnetic resonance, infrared spectroscopy) and mass spectrometry, along with elemental analysis, to determine the exact structure.

In chemical databases and literature, C9H9NO3 serves as a common reference formula used to catalog and distinguish members of this class. Such compounds frequently arise as intermediates in organic synthesis, dyes, or pharmaceutical research.