While perfluorinated aryl, aryloxy and alkoxy aluminum species are well-established as weakly coordinating anions (WCAs), corresponding perfluoroalkyl aluminum derivatives are virtually unknown. Reaction of Si(C 2 F 5 ) 3 CH 3 with Li[AlH 4 ] afforded the tetrakis(pentafluoroethyl)aluminate, [ Al(C 2 F 5 ) 4 ] - . Several salts of the [ Al(C 2 F 5 ) 4 ] - ion were synthesized and characterized by NMR spectroscopic methods, mass spectrometry, X-ray diffraction studies and elemental analysis. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.