Ionic–covalent equilibria in boron trihalide adducts. The BF2(hmpa)2+ cation
Abstract
The reaction 2 hmpa·BF3⇌ BF2(hmpa)2++ BF4– occurs spontaneously in the hexamethylphosphoramide (hmpa)–BF3 system. The degree of ionization for the above reaction is 0.13 in CDCl3 solution at 27 °C. Factors favouring the relatively rare ionic form of boron trifluoride adducts are discussed.