C4H5NO2

C4H5NO2 is the molecular formula for a family of organic compounds that share four carbon atoms, five hydrogen atoms, one nitrogen atom, and two oxygen atoms. As an empirical or molecular formula, it represents multiple possible constitutional isomers rather than a single, specific compound. The exact structure—and thus many properties—depend on how the atoms are arranged.

The nominal molecular weight of C4H5NO2 is about 99.09 g/mol. The formula has a degree of unsaturation (DBE) of 3, indicating three rings and/or multiple bonds in the most common isomeric forms. The presence of one nitrogen and two oxygens allows a range of functional groups, such as carbonyl-containing moieties and potential heterocyclic rings, but the specific functionality varies with the isomer.

Because many distinct structures share this formula, structural identification requires spectroscopic data. Nuclear magnetic resonance, infrared spectroscopy, and mass spectrometry—or, when possible, crystallography—are used to determine the exact isomer. Without such data, C4H5NO2 cannot be assigned to a single compound.

In practice, compounds with this formula may appear as intermediates or fragments in organic synthesis and analytical contexts. They can serve as building blocks for heterocycles or as derivatives in medicinal chemistry research, with properties and applications determined by the precise arrangement of atoms. Safety and handling depend on the specific isomer involved.