The gas-phase ion chemistry of BF3/CH4 mixtures was investigated by the joint application of mass-spectrometric and ab initio theoretical methods. The addition of BF2+ to CH4 led to the observation of BF2CH4+ and BFCH3+ ions in the gas phase. Collisionally activated dissociation (CAD) mass-spectrometric results and theoretical calculations performed at the B3LYP and CCSD(T) levels identified the F2B-CH4+ and F-B-CH3+ ions as the most stable isomers on the [BFnCHn+2](+) (n = 1, 2) potential energy surfaces. It is worth noting that C-N bond formation was observed when BFCH3+ ions were allowed to react with NH3. (C) 2008 Elsevier B.V. All rights reserved.