The Trifluoromethyl Anion

First evidence for the existence of free trifluoromethyl anion CF3− has been obtained. The 3D‐caged potassium cation in [K(crypt‐222)]+ is inaccessible to CF3−, thus rendering it uncoordinated (“naked”). Ionic [K(crypt‐222)]+ CF3− has been characterized by single‐crystal X‐ray diffraction, solution NMR spectroscopy, DFT calculations, and reactivity toward electrophiles. Evidence (X‐ray, NMR, reactivity studies, DFT) has been obtained for the existence of the “naked” trifluoromethyl anion CF3−. In [K(crypt‐222)]+ CF3−, the 3D‐caged potassium cation is inaccessible to CF3−, which makes it uncoordinated (“naked”).