Tetramethylammonium pentafluoroxenate
Tetramethylammonium pentafluoroxenate is a chemical compound with the chemical formula. This salt consists of tetramethylammonium cations and pentafluoroxenate anions. The ion was the first example of a pentagonal planar molecular geometry [VSEPR theory|] species. It was prepared by the reaction of [Tetramethylammonium fluoride|] with xenon tetrafluoride, being chosen because it can be prepared in anhydrous form and is readily soluble in organic solvents. The anion is planar, with the fluorine atoms in a slightly distorted pentagonal coordination. Other salts have been prepared with sodium, caesium and rubidium, and vibrational spectra show that these contain the same planar ion. The isolated anion has the point group of D5h.