Tags: Chemical Compound, Chemical Substance.
Tetramethylammonium hydroxide (TMAH or TMAOH) is a quaternary ammonium salt with the molecular formula N(CH3)4+ OH− and is one of the simplest members of this class of organic compounds. This substance is known in a (relatively) stable solid form only as the pentahydrate. Commercially the forms in which TMAH is most commonly encountered are as concentrated solutions in water or methanol. The solid and solutions are colorless or yellowish if impure.
