C8H6O

C8H6O is a molecular formula representing a family of organic compounds that collectively contain eight carbon atoms, six hydrogen atoms, and one oxygen atom. The formula has a molecular weight of approximately 118.14 g/mol. The index of hydrogen deficiency for this composition is 6, indicating a high degree of unsaturation consistent with aromatic systems, multiple rings, or carbon–carbon or carbon–oxygen double bonds.

Because C8H6O corresponds to many possible structures, there is no single canonical compound associated with it. Isomers of this formula commonly fall into categories such as oxygen-containing aromatic carbonyl compounds (for example aldehydes or ketones) and polycyclic or fused-ring systems that incorporate a single oxygen atom in a carbonyl, ether, or heteroaromatic setting. The exact arrangement of atoms can vary widely, leading to considerable structural diversity even with the same empirical formula.

In practice, identification and characterization rely on spectroscopic methods. Mass spectrometry provides the molecular weight and fragmentation patterns, while infrared spectroscopy can indicate functional groups (such as carbonyl or ether linkages). Nuclear magnetic resonance (NMR) spectroscopy and, when needed, X-ray crystallography help determine the precise connectivity and geometry of the isomer.

C8H6O occurs in contexts ranging from academic studies of isomerism and aromatic chemistry to analytical investigations of complex mixtures where such formulas may appear as fragments or trace constituents. See also molecular formula; isomerism; aromatic compounds.