First evidence for the existence of free trifluoromethyl anion CF 3 À has been obtained. The 3D-caged potassium cation in [K(crypt-222)] + is inaccessible to CF 3 À ,t hus rendering it uncoordinated ("naked"). Ionic [K(crypt-222)] + CF 3 À has been characterized by single-crystal X-rayd iffraction, solution NMR spectroscopy, DFT calculations,a nd reactivity towarde lectrophiles.