Tetraethylammonium

Tetraethylammonium (TEA) is a quaternary ammonium cation with the chemical formula [Et₄N]⁺, consisting of four ethyl groups (−C₂H₅, denoted Et) attached to a central nitrogen atom. It is a counterion used in the research laboratory to prepare lipophilic salts of inorganic anions. It is used similarly to tetrabutylammonium, the difference being that its salts are less lipophilic, more easily crystallized and more toxic.

Tetraethylammonium is a potassium channel blocker. It inhibits the return to the resting potential of action potentials in neurons by binding to the voltage-gated potassium channels in nerve cell membranes and blocking the passage of potassium ions (responsible for the repolarization of an action potential) out of the neuron.