Phenol is an organic compound with the chemical formula C6H5OH. It is a colorless, needle-like crystal with a distinctive odor, is toxic, and serves as an important raw material in the production of certain resins, fungicides, preservatives, and pharmaceuticals (such as aspirin). It can also be used for disinfecting surgical instruments, treating excreta, and as an antiseptic and antipruritic for the skin, as well as for treating otitis media. Its melting point is 43°C. At room temperature, it is slightly soluble in water but easily soluble in organic solvents. When the temperature exceeds 65°C, it can mix with water in any proportion. Phenol is corrosive and causes local protein denaturation upon contact; solutions spilled on the skin can be washed off with alcohol. A small portion of phenol is oxidized by oxygen in the air to quinone, turning pink. It turns purple when exposed to ferric ions, a reaction commonly used to test for phenol.