The Autoionization of [TiF4] by Cation Complexation with [15]Crown-5 To Give [TiF2([15]crown-5)][Ti4F18] Containing the Tetrahedral [Ti4F18]2− Ion

It's the crown that does it: The auto‐ionization of [TiF4] has been promoted by complexation with [15]crown‐5 to produce [TiF2([15]crown‐5)][Ti4F18], which contains the new tetrahedral ion [Ti4F18]2− (see picture). The thermodynamics of the [Ti4F18]2− ion relative to the [Ti2F9]− ion in the gas, solution, and solid states were calculated by density functional methods.