Hexamethylphosphoramide, often abbreviated HMPA, is a phosphoramide (i.e. an amide of phosphoric acid) having the formula [(CH3)2N]3PO. This colorless liquid is a useful polar aprotic solvent and additive in organic synthesis. ==Structure and reactivity== HMPA is the oxide of the highly basic tertiary phosphine hexamethylphosphorous triamide (HMPT...