TeO3^2-, or tellurite, is a polyatomic ion composed of one tellurium atom and three oxygen atoms, carrying a -2 charge. It is commonly found in various chemical compounds and can act as a reducing agent in certain reactions. Tellurite is often encountered in the context of inorganic chemistry and can form salts with different cations. Its properties and behavior are significant in fields such as materials science and environmental chemistry, where it may play a role in the biogeochemical cycling of tellurium.