C6H4NO2

C6H4NO2 is the molecular formula for several isomers, most notably nitrobenzene and nitrophenol. Nitrobenzene has the chemical formula C6H5NO2 and is an aromatic organic compound. It is a pale yellow, oily liquid with a characteristic almond-like odor. Nitrobenzene is primarily used as a precursor to aniline, which is then used in the manufacture of dyes, polyurethane foams, and rubber chemicals. It can also be used as a solvent and in the production of explosives. Nitrobenzene is toxic and can be absorbed through the skin, causing methemoglobinemia, a condition that reduces the blood's ability to carry oxygen.

Nitrophenols are a group of organic compounds where a nitro group (-NO2) and a hydroxyl group (-OH) are attached to a benzene ring (C6H4). The position of these groups determines the specific isomer. For example, 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol are distinct compounds with different properties. Nitrophenols are often yellow crystalline solids and can be acidic due to the electron-withdrawing nature of the nitro group. They find applications as intermediates in the synthesis of dyes, pharmaceuticals, and pesticides. Some nitrophenols can also exhibit toxicity. The chemical formula C6H4NO2 strictly represents a fragment or a radical, but in common chemical nomenclature, it often refers to the isomers derived from attaching both a nitro group and a hydrogen atom to a benzene ring in a way that the remaining structure can be represented as C6H4. However, when referring to stable, neutral molecules with this elemental composition, nitrobenzene (C6H5NO2) is the most common compound associated with a similar structure.