C9H7NO
C9H7NO is the molecular formula that can describe several isomeric organic compounds, rather than a single specific molecule. Because the formula contains one nitrogen and one oxygen, a family of structures with a benzene ring fused to a nitrogen-containing heterocycle is commonly encountered. The exact structure depends on how the atoms are arranged, particularly the position of the carbonyl group and the ring fusion pattern.
The best-known representatives of this formula are the quinolinones, also called quinolin-ones. The two principal isomers
In summary, C9H7NO denotes a formula associated with the quinolinone family as its most prominent example,