- o-Nitrophenol (1-hydroxy-2-nitrobenzene; OH and NO2 groups are neighboring; CAS number: 88-75-5), a yellow crystalline solid (m.p. 46 °C).
- m-Nitrophenol (1-hydroxy-3-nitrobenzene, CAS number: 554-84-7), a yellow solid (m.p. 97 °C) and precursor to the drug mesalazine (5-aminosalicylic acid).
- p-Nitrophenol (1-hydroxy-4-nitrobenzene, CAS number: 100-02-7), yellow crystals (m.p. 114 °C). It is a precursor to the rice herbicide fluorodifen and the pesticide parathion.
The nitrophenols are produced industrially by the reaction of chlorides with sodium hydroxide at temperatures around 200 °C. The mononitrated phenols are often hydrogenated to the corresponding aminophenols that are also useful industrially.
Di- and trinitrophenols
Nitrophenols are poisonous. Occasionally, nitrophenols contaminate the soil near former explosives or fabric factories and military plants, and current research is aimed at remediation.