Electron impact on fluorinated acetyl compounds RCOF(3) (R=OH, OSi(CH3)(3), OCH3, CF3COCH2, CH3COCH2, CH3, 3,5-(CF3)(2)C6H3CH2) in an FT-ICR spectrometer yields ionic products of m/z=[M-HF]. These products are proposed to arise via a two-step mechanism : upon electron impact the neutral precursor gives a fluoride ion-neutral radical complex followed by a secondary reaction of the fluoride anion with the neutral radical, either nucleophilic substitution or proton transfer, to yield a biradical anion (distonic radical anion). These radical anions were isolated and their chemical properties were studied. They undergo reactions characteristic of closed-shell anions, e.g. proton transfer, or characteristic of open-shell species, e.g. radical addition-elimination reactions.