C9H6

C9H6 is a molecular formula representing several organic compounds, most notably benzene derivatives with varying degrees of unsaturation. The simplest and most well-known compound with this formula is **styrene** (vinylbenzene), a colorless, flammable liquid with a sweet odor. Styrene is a key industrial chemical used primarily in the production of polystyrene and other synthetic resins, including ABS plastics and styrene-butadiene rubber. It is derived from ethylbenzene through catalytic dehydrogenation and is a critical monomer in polymer synthesis.

Another compound with the formula C9H6 is **indene**, a bicyclic aromatic hydrocarbon featuring a five-membered ring fused to a benzene ring. Indene is a colorless liquid with a strong, aromatic odor, often found as a byproduct in coal tar distillation. It serves as a precursor in the synthesis of various chemicals, including pharmaceuticals and dyes, and is also used in the production of certain types of resins.

A third isomer, **benzocyclobutadiene**, is highly unstable and reactive due to its antiaromatic nature, meaning it does not follow the usual stability rules for aromatic compounds. This compound has been synthesized under controlled conditions and studied for its unique chemical properties, though it decomposes rapidly at room temperature.

The C9H6 formula can also represent other less common or transient species, such as partially hydrogenated derivatives or radical intermediates in organic reactions. Due to its versatility, styrene is the most commercially significant compound associated with this molecular formula, driving its widespread use in manufacturing and materials science.