Triethylborane is a chemical compound with the formula C9H27B. It consists of three ethyl groups attached to a boron atom, making it a member of the organoboron compounds. Triethylborane is a colorless liquid that is highly reactive, particularly with oxygen and moisture, which can lead to the formation of boric acid. This compound is primarily used as a reagent in organic synthesis and as a catalyst in various chemical reactions. Its reactivity makes it valuable in the production of alkenes and alkynes, as well as in the polymerization of certain monomers.