Tetraethylammonium bromide is a quaternary ammonium salt consisting of a positively charged tetraethylammonium cation and a negatively charged bromide anion. This compound is commonly used as a phase transfer catalyst in organic chemical reactions, facilitating the transfer of reactants between immiscible phases. It can also be used as a reagent for the synthesis of various organic compounds, an electrolyte in electrochemical experiments, and a source of tetraethylammonium ions in biochemical and pharmacological research.