C4H7O2

C4H7O2 is a molecular formula that denotes four carbon atoms, seven hydrogen atoms, and two oxygen atoms. In ordinary neutral organic chemistry, this exact composition does not correspond to a stable, closed-shell neutral molecule. The degree of unsaturation (DBE) for C4H7O2 is calculated as 4 − 7/2 + 1 = 1.5, which is not an integer. Because DBE must be an integer for neutral molecules, any neutral compound with this exact formula would be unexpected. As a result, when C4H7O2 is encountered as a discrete composition, it typically indicates an ionic, radical, or fragment species rather than a conventional neutral compound.

In practical terms, C4H7O2 is most often seen in contexts such as mass spectrometry or theoretical chemistry as an ion, radical, or fragment rather than as a standalone, isolable neutral substance. The formula is compatible with a four-carbon backbone carrying two oxygen-containing functional groups, but the exact structure cannot be determined from the formula alone. Any proposed identity would rely on additional data such as spectroscopic information, charge state, and fragmentation pathways.

As a reference point, other formulas with four carbons and two oxygens that do exist as neutral compounds include C4H8O2 (for example, certain esters or butanoic acid derivatives) and C4H6O2 (such as gamma-butyrolactone). C4H7O2 serves mainly as a compositional descriptor rather than a specific, well-defined neutral substance. See also: molecular formula, degree of unsaturation, isomer.