It is a kind of polycyclic aromatic hydrocarbons, which have fluorescence when impure, and the formula is c13h10. White flake crystals having a characteristic aromatic odor similar to naphthalene. It exists in the high boiling-point components of automobile exhaust gas, corn whiskers and coal tar. Flammable. Used in the manufacture of medicine (the production of anti-spasm drugs, sedatives, analgesics, antihypertensive drugs), dyes (in lieu of anthraquinone synthesis of Shan Danslin dyes), synthetic pesticides, herbicides, shock-resistant plexiglass and FMOC resin, used as wetting agent, detergent, Liquid flasher, disinfectant and so on. Used as raw material for organic synthesis; it can be made into three-nitro-ketone, used for electrostatic copying and synthesis of aromatic transparent nylon.